You: a happy winemaking citizen, going about your lawful fermentation business, enjoying the marvellous convenience and quality that the wine-kit industry has provided you.
Your kit wine: usually a tractable and pleasant beverage, it suddenly turns on you and does something it has never done before. How can this be? What can you do?
First, don’t panic. Second, don’t discard your wine. Third, read on! Fourth, don’t feel bad. Regardless of how strange your wine may be behaving, you are definitely not the first person to experience it. In the ten years I’ve worked at wine kit companies, I’ve just about heard it all, from “My dog ate my additive packages” to “Is wine supposed to shoot out onto the ceiling?”
The good news, though — if I might toot the industry horn — is that the failure rate of kits is very low. If you follow the instructions closely and have generally sound sanitation and storage practices, along with a healthy dose of patience and the good sense to take and record specific gravity and temperature readings, you’ll make good wine 99.9% of the time.
However, there is that teeny percentage when the kit goes sideways, and something a little stronger than patience is required. That’s when it’s time for take-no-prisoners troubleshooting. This article is divided into three sections: fermentation problems (slow, fast or unfinished), visual problems (clarity and color), and odor problems (aroma, bouquet and stink).
BUT FIRST . . . you need to carefully re-read your kit instructions. Wine kits sometimes have instructions and procedures that contradict accepted techniques for fresh grape winemaking or for other kinds of kits. There are many good reasons for these non-intuitive procedures, but they all boil down to the same thing: that’s the way that this specific kit ferments, clears and stabilizes best, as proven by numerous lab trials. Departing from the instructions is the number two route to failure that we see in the quality control laboratory. (The first? Sanitation!)
These fixes, while applicable to almost all wines, are specifically designed to work with kits. Kits, as I am fond of pointing out, are not the same things as fresh grapes and fresh juice. Not only do you need to follow the right directions for the kits, you also have to apply the correct fixes!
This article will frequently refer to checking temperatures and specific gravity readings. To troubleshoot your wine kit problems you’ll need a good floating thermometer, a test-jar and a hydrometer. Without these tools, no troubleshooting article will help you find the right fix.
Ultimately, the key to the cure in most of these cases is prevention, and the best way to improve your winemaking is to keep good and careful records. That way you’ll be able to diagnose your problems, repeat your successes, and avoid future problems.
Fermentation Follies: Wine Won’t Ferment
1. The Gravity of the Situation
When yeast is pitched according to kit instructions, you should see activity within 48 hours, or at least a nice, healthy scum of developing yeast on top of the must. If not, the first step is to take a specific gravity reading (you did take one when you made the kit up, riiiight?). If it shows a drop from the original, you’re experiencing “secret yeast.” For several and complex reasons, sometimes yeast like to hide, quietly getting to work without too much foaming or fizzing. In this case the immediate solution is to relax and to take another specific gravity reading a day later.
2. Did You Really Add It?
If the gravity has not dropped, double-check that you have actually added the yeast. On the first day, sometimes the multiple activities expected of you (adding the right amount of water, at the right temperature, stirring in additives, etc.) can get confusing. If you find your package of yeast sitting inside the box, or think you may have discarded it, add yeast immediately. If you can’t find the package that came with the kit, make sure you add an identical strain to the one recommended by the kit manufacturer: It’s the only way to be sure that your kit turns out the way it was intended. Check your gravity for the next three days to make sure that fermentation is proceeding correctly.
3. Cool Things Down …
If you know you added yeast, check the temperature of the must. Kit wines are all designed to ferment at room temperature, generally a range of 65 to 78 °F or so. (RTI — read the instructions!) If it’s much above 90 °F, you may have added too much hot water to the must, and the yeast is likely dead. Cool the must by freezing a couple of bottles of water, sanitizing the outside and dropping them into the fermenter. Alternately, you can drape a wet towel or T-shirt around the fermenter and direct a fan at it. When the temperature is below the recommended maximum in your instructions, pitch a fresh package of yeast.
4. . . . Or Heat Things Up
If the temperature of the must is below 65 °F, warm the must up by wrapping it with a heating belt (available through your supply shop). Don’t set it on a heating pad or blanket: This concentrates the heat and can cause electrical damage, or even a fire (not to mention what it would do to the wine!). Most of the time the yeast will begin fermenting within 24 hours, but if not, double-check the temperature of the must and pitch another package of yeast.
There is a definite window of opportunity for correcting the must temperature or adding a missed package of yeast: if you catch it within four days, you can probably get it going without repercussions. Keep in mind, however, that unprotected grape juice is an excellent growth medium for all kinds of bacteria: If the must smells sour or looks moldy, you are probably out of luck. In any case, monitor your fermentation for signs of contamination during the rest of the process.
If you’ve added the yeast, the temperature is okay, and it’s still not fermenting within 24–48 hours, have a careful look for the additive packages that came with the kit. If you have accidentally added the stabilizers to the kit, you may have a terminal problem on your hands.
5. Adding Sulfite Early
If it’s just the sulfite that was mistakenly added, sometimes a very strong yeast starter culture can overcome moderate levels of free sulfur dioxide. Start a package of yeast in a quart of commercial apple juice heated to 75 °F, along with a teaspoon of yeast nutrient. Shake the bejabbers out of the juice and nutrient mixture before adding the yeast, as a little dissolved oxygen will help the yeast get started. After 24 hours, or the onset of very vigorous activity, pitch the entire quart into your must. Don’t worry about the flavor: It won’t be significant, and a small flavor change is less important than getting your must started ASAP. If you have added more than 50 PPM of extra sulfite (the equivalent of a half-teaspoon per six gallons) there are some things you can do to lower the sulfite content. Look in the section on odor problems, below.
Another couple of good restarting techniques: Take a wine that is ready to be racked from the primary fermenter to the carboy, and harvest the yeast sediment remaining after the wine has been racked. By far the best way to do this is to leave the yeast sediment in the primary fermenter and pour the non-fermenting must in on top of it. Finish up with a good stir, to get all of the yeast into suspension.
6. Sore Point: Sorbate
If you’ve added the sorbate package included in the kit, discard the wine. Sorbate prevents yeast breeding, and virtually all efforts at starting fermentation in the presence of sorbate fail.
7. Yeast At Least
If you’ve avoided all the above conditions, and your wine still won’t ferment, your yeast may have been inactive. A fresh package should get things on the road. Make sure it’s the same variety and type of yeast included in the kit.
8. Extra Nutrient: Not Part of a Nutritious Fermentation
One thing that may seem like a good idea, but actually doesn’t work with wine kits, is adding extra yeast nutrient. Wine kit manufacturers all add very nearly the maximum amount of yeast nutrient a kit can handle. It’s not going to be a low-nutrient situation that hampers your fermentation, and extra nutrient will stay behind in the wine and leave a salty-bitter flavor.
Wine is Fermenting too Quickly or Slowly
1. Is it Hot in Here?
If your wine ferments to dryness in less than half the time required in the instructions, your temperatures may be too high. Try the wet towel trick described above to cool it down. The trouble with hot fermentation is that yeast tends to generate its own heat after a certain point, and you could have a heat-related yeast die-off and a stuck fermentation later.
2. Timing is Everything
If your wine ferments to dryness in less time than specified in the kit instructions, wait the minimum amount of days indicated in the instructions before racking to the secondary fermenter. For example, if the instructions say to wait 5 to 7 days, until the gravity is below 1.020, and you achieve 1.020 on the third day, cool the fermentation down to the temperature specified in your instructions and wait until day 5 before racking. This will ensure that an appropriate amount of sediment is left behind in the primary, and could prevent problems with fining and clearing later.
Once in a while we see a kit that has been racked from the primary too soon that has a large amount of oak chips still in suspension. These can collect in the airlock and block it off, causing pressure to build up until suddenly . . . it’s Krakatoa Cabernet.
If you do find your wine shooting out of the airlock, you’ve racked it into the carboy too soon. Rack it back into the primary and wait for it to hit the correct gravity. Don’t be fooled if it calms down immediately after racking. All that has happened is that the CO2 has been knocked out of solution by the agitation of racking and the wine will soon be foaming vigorously again.
If your fermentation is proceeding too slowly, try warming your must up to the recommended temperature, and practice patience. Don’t rack the wine on day 7 if the specific gravity is higher than recommended. Wait for the appropriate gravity before racking your wine.
3. Steady as She Goes
One thing that I frequently see hampering fermentation schedules is repeatedly fluctuating temperature. Most of us never think about it, but when we leave for the day we turn the furnace off, dropping ambient temperature in our fermentation area, and when we come home, we warm our house up. This drives yeast crazy, and it can often cause it to go dormant, while it waits for more favorable conditions. You may need to isolate your fermenter in an area with a more steady ambient temperature.
Wine Won’t Quit Fermenting
1. Zero In On Gravity
Sometimes a carboy will continue to bubble, long after it should have stopped. First things first: check your specific gravity. If it’s high, give the wine a good stir, make sure the temperature is at the high end of the specified range and practice patience yet again.
2. Fake Fermentation
If it’s in the right range, as listed in the instructions, you may be experiencing one of two phenomena. First, your wine may actually be finished fermenting, but due to changes in temperature or barometric pressure it is out-gassing carbon dioxide at a rate that looks like active fermentation. This could be exacerbated if your wine fermented quite slowly (as in a cool fermentation) and is saturated with CO2.
3. Microbiological Party-Crashers
The other possibility is that the wine is being fermented by an organism that can continue to access nutrients long after the cultured yeast has finished. This could be a random bacteria from the environment (most commonly a lactic acid bacteria, like a spontaneous malolactic fermentation) or a mutant or indigenous yeast. In this case, when the wine has hit its target gravity, and the requisite number of days have passed, it is imperative that you proceed with the stabilizing and clearing procedures in the instructions. By stabilizing in a timely fashion (at the correct specific gravity) you’ll prevent organisms from doing any significant damage to the kit.
MY WINE DOESN’T LOOK RIGHT!
The Wine Won’t Clear
First, don’t bottle cloudy wine. It won’t clear in the bottle, and any extra treatment to clear it up will require you to dump out all the bottles, process it and re-bottle.
1. Steer Clear of Filtering
Second, don’t filter the wine to clear it. Filtering is only good for clearing wines that are already almost completely clear. Fining agents still in suspension will sail straight into your filter pads, blocking them up quickly, and the ones that make it through will show up as sediment later on!
2. Fining: Stir Things Up
First go back to the instructions (yes, again) and carefully review them to make sure you followed the fining procedures exactly. Some kits want you to add bentonite on the first day, and some want it on the 20th. Some kits must be racked prior to fining, some must not be racked or the finings won’t work at all. Also, the instructions regarding fining all contain the same curious phrase: “Stir vigorously.” Which actually means really, really, really vigorously. In order for the finings to have the proper effect on the wine it needs to be free of carbon dioxide. If it’s not, the bubbles of CO2 will float the fining particles back into suspension, over and over again, and nothing will settle out. So stir the wine until it stops fizzing. This process may be helped if you warm the wine to the upper end of the specified temperature range (remember CO2 is soluble in a liquid solution in inverse proportion to the temperature).
3. It’s Fined, But Is It Finished?
This leads to the next step: check the specific gravity. If the wine had not finished fermenting before you added the finings, you’re just going to have to wait until it does. Nothing you do will influence the clarity until the yeast is done.
4. Hot and Cold Finings
If all of these things are in order, check the instructions regarding temperature. While some fining agents work well under cool temperatures (such as bentonite or kieselsol), others (chitosan, isinglass) stop working when it gets chilly.
5. Patience, Grasshopper
If your gravity is correct, and you’ve stirred the wine, and you’ve got it at the right temperature, simply wait an extra week and see if it clears up on its own. The principle of least intervention applies to all fining activities: Try to get the most effect with the least amount of added finings and effort.
6. More Fining
If a few weeks’ patience doesn’t pan out, you can probably add an extra dose of finings. Usually a manufacturer will recommend the same fining agent used in the kit, at a rate of 50% of the original dose. If that turns out not to be an option, Sparkolloid is an excellent choice. The combination of seaweed protein and diatomaceous earth makes it a very effective clean-up fining. Use sparingly and follow the package directions precisely.
If you do wind up stirring extra fining agents into the kit, make sure you increase the sulfite levels. As a rule of thumb, you can add an extra one-quarter teaspoon of metabisulfite per 6 US gallons (25 parts per million) to offset any oxidation from the handling.
Clear Wine Goes Cloudy in the Bottle
If your wine seemed clear in the carboy, but after bottling showed a haze or sediment, you have one of three problems:
1. Fermentation Not Finished
You can determine if the wine is continuing to ferment in the bottle by taking a sample and checking both the specific gravity and the level of CO2. If the specific gravity is higher than that recommended in your instruction for bottling, and it has a significant amount of CO2, you will need to un-bottle all of it and let it finish fermenting. There’s nothing more disappointing than coming home to discover a bunch of miniature wine-volcanos popping corks and spewing red wine onto your Bokhara rugs! Well, unless it’s coming home and discovering that your batch has turned into thirty glass hand grenades.
2. Fermentation Contamination
If the specific gravity is at or below the levels recommended in your instructions, but the wine is fizzy with CO2 and hazy, you may have a microbial infection. There are thousands of potential culprits, from lactic acid bacteria (spontaneous malolactic) to Acetobacter (vinegar) to air-breathing mutant yeast: All will ferment your wine after it has achieved what should be your terminal specific gravity. In this case you will need to un-bottle it all, re-stabilize it with more sulfite, and filter it. It will need to remain in the carboy until you are completely sure it will not ferment again in the bottle.
3. A Good Source of Protein
Protein haze is by far the most common of the three scenarios. Sometimes a fining agent will fail to clear all of the big proteins in a wine kit, or in some cases, traces of a protein-based fining agent (gelatin, isinglass) will stay in solution. When the temperature of the wine changes, these proteins become visible as a haze. As it warms up again, the haze disappears. Proteins are usually taken care of with the bentonite included in kits, but if you do have a protein haze, a small addition of bentonite should take care of it. Try adding 15 grams per six gallons (three teaspoons). Wait two weeks and check for cold stability.
If the wine is mostly clear at room temperature, but clouds when cold, you can chill the batch and, while it is still cold, filter the haze out. (This will not work if the wine contains significant amounts of sediment.) Use the finest grade of filter pads.
Floaties in the Wine
Lumps on Top of the Wine
1. Identify Your Floaties . . .
During the early stages of fermentation yeast can sometimes clump together and float on top of the must. Occasionally mold can form on top of the wine, showing up as small, papery-looking dots or circles. To discern between yeast and mold, take a sample of the floating material and rub it between your fingers. Yeast smears like yogurt or sour cream. Mold will roll up like rubbery paper and won’t smear at all.
2. . . . And Bring Them to Justice
If it’s yeast, ignore it. Yeast floating around the top of the must constitutes unremarkable behavior. But if it’s mold, you need to assess the wine. If the mold came out of the bag when you made the kit, you should document the kit serial number, grab a sample of the mold and must in a sanitized container and return to your retailer with your receipt in hand.
3. Where They Come From
Because of the way the wine is packaged, through a sterile-fill pasteurizing head, it theoretically goes into the bags free of organisms. But certain environmental molds are actually thermophilic, meaning they don’t bloom until after they’ve been heated beyond a certain point. These organisms can survive the pasteurizing process and show up in the wine a few weeks after packaging. We track this like hawks—that’s why you need the serial number, receipt and sample.
4. Other Villains
If you see something floating on your wine after it has been stabilized and fined, it could again be clumped yeast (stir harder to release CO2 so the clumps sink) or it might be an aerobic organism, like mycoderma or Acetobacter (see the sections on films below). It won’t be mold, as mold can’t grow in a low-pH environment with alcohol above 3%.
Film On Top of the Wine
1. Don’t Send Flowers
With mycoderma you’ve got trouble. It can manifest as a fine film on top of the wine, sometimes called “flowers of wine.” It and Acetobacter only grow in aerobic, or oxygen environments. This means carboys that aren’t topped up according to instructions, and wines that do not contain sufficient sulfite. Mycoderma is actually a species of yeast (Candida vini) that breathes air. If detected soon enough you can sometimes treat the wine with a measured dose of sulfite (50 PPM, or a half-teaspoon of sulfite powder per 6 US gallons) followed by racking to get it off of any mycoderma sediment. Top the wine up to the neck of the carboy, use a solid bung, and taste the wine after a week to see if you caught it in time. You may wish to re-test the wine for sulfite level and filter it to keep it stable. Then go through all of your equipment and sterilize it by soaking it in a chlorine solution and scrubbing with plenty of elbow grease. Check all of your other wines, being careful to sanitize your wine thief and sample jars between wines. Mycoderma easily spreads to other wines and is difficult to get rid of.
A word about chlorine solutions: The most common one is a pink, chlorinated-phosphate detergent sold under the trade names “Sparkle Brite” or “Sani-Brew.” Originally from the dairy industry, it is also used for sanitizing milk-processing equipment. It not only cleans effectively, but also destroys the physical body of spoilage organisms. Mere sulfite or detergent can’t accomplish this, and infections like mycoderma or the other ones listed below warrant a take-no-prisoners effort. Be careful to follow the instructions for use, and avoid contact with metals like aluminum (which can produce irritating gases) and stainless steel, which chlorine can pit and etch.
2. Don’t Be Flor-ed.
Some people see a film on their wine and think that they have a sherry or “flor” yeast. This is a type of yeast that behaves as strangely as its cousin mycoderma, using oxygen and leaving a film (or “flor”) on top of the wine. As it works it can drive the alcohol content of the wine to 20% or higher, and leaves it with a nutty, delicate flavor described as “rancio” by sherry makers. The truth is, flor grows under such an incredibly narrow range of conditions (temperatures in excess of 100 °F, lots of dissolved oxygen, no sulfite and a huge culture of the proper yeast strain) that you will never see it unless you devote your life to growing it.
Swirly Goo in Wine
1. Your Mother
Acetobacter is the jerky brother-in-law of spoilage organisms: It consumes your alcohol and leaves you with a sour taste in your mouth. It breaks alcohol down into acetic acid and associated ketones, esters and aldehydes, giving wine that distinctive vinegar odor and back-of-the-throat tang, utterly ruining it forever. It can manifest itself as a swirly-looking ghost in the wine, known as “mother of vinegar.”
2. The Cure
The cure for Acetobacter contamination is a sewer drain. Sanitize all of your equipment like a demon, all at once, with chlorine-based solutions. Top up all carboys of finished wine, make sure airlocks and bungs are secure and full of water or sulfite solution, use the recommended level of sulfite in your kit—and pray to the gods of bibulousness for better luck next time.
3. The Culprit
If there were more room in this story, I’d describe the fascinating life cycle of the fruit fly, Melanogaster drosophilia, and his role as the primary carrier of Acetobacter. However, the rule of thumb is: Wipe up all spilled wine and juice, treat all surfaces with sulfite solution and don’t keep bananas in the winery. If you do get a fruit-fly infestation, get some food-grade insecticide. One popular brand is “Gard-Mist.” It’s safe for use in food preparation areas. But it can make people with ragweed allergies sneeze, so do be careful and read the label before using.
Wine Looks like Ropey Goo
1. Toss a Rope
Another entirely wacky phenomenon in wine appearance is “rope,” or “graisse.” The yeast exudes a mucus-like polysaccharide compound and thickens the wine like, well, 6 gallons of mucus. In extreme cases you can actually use your finger to scoop out a thick ribbon of wine. This condition, while fascinating, is rare even in the worst of third-world winemaking conditions. If you manage to induce this in a wine kit, please accept my congratulations on your amazing skill. Throw your wine away, burn all of your equipment and don’t buy any more.
That’s not the Right Color!
Kit is too dark or too light
1. Inconsistent Kit Color
Wine kit manufacturers are in an odd position: They make a packaged food out of a variable agricultural product. In this respect they are like producers of bread or pasta, who face harvest differences from year to year. They both blend raw materials from different areas to achieve consistent quality — kit manufacturers using grapes, rather than wheat, in this case.
However, even when all of the grapes in a kit come from a specific area, it may not be possible to completely blend away the color and flavor differences. Commercial wineries acknowledge this, and celebrate the different harvests by doing vintage tastings. Kits, however, are going to vary a bit from year to year, and unless the color change is marked by some other change (such as a loss of aroma or bouquet) you may not want to do anything to change it.
2. If You Want to Change
There are coloring products on the market, such as Grapeskin Extract and Exberry, which can be used to darken a red wine. If you must use them, follow the package directions, but keep in mind that they are not very stable colors, and could combine with any proteins or melanoidins in the wine and fall out of suspension later on.
3. See the Light
It hardly ever happens that a kit is darker than expected, but if it is, double-check with your retailer to make sure you got what you were asking for. If it’s the correct style, but still too dark for you, you may wish to blend it away into a lighter wine in the future.
Pink Wine is Orange
Blush wines are actually quite difficult to produce, and commercial wineries have spent literally millions of dollars trying to figure out how to keep the color in their blush. The color compounds that give a blush or a “white” Zinfandel (or Merlot) its lovely pink color lose their purple-pink hue over time and go to a reddish-brick pink. The French call this color “l’oeil de perdrix” (eye of the partridge) and it almost looks like the color of salmon flesh. This change is not a sign that the wine is oxidizing or spoiling, merely that the colors are going through their natural evolution. Red wines do the same thing, but they have much higher levels of color, and more importantly they have higher levels of tannin and polyphenolic compounds which stabilize the color. Unless this color is accompanied by off aromas and flavors, it isn’t a sign of low quality.
White is Brown, Red is Brick
1. Identify Oxidation
While well-aged examples of white wine can be deep golden and sherry is a lovely tawny-toast color, brown wine is usually a sign of advanced oxidation, and is accompanied by a sherry-like smell due to acetaldehyde production. When terminally advanced this sherry smell goes from acetaldehyde to acetic acid to ethyl acetate, the vinegar and nail polish remover aromas described below. The best treatment is prevention, so follow your kit instructions for racking, topping and sulfite use.
2. Lighten Up
But, if you get caught out, in early stages one can treat the wine first with a strong dose of sulfite (50 PPM, one-half teaspoon per 6 US gallons) and then with a compound that removes oxidized melanoidins (color compounds). The best of these is Polyclar (food-grade polyvinylpolypyrrolidone or PVPP, a type of powdered nylon). Use according to instructions, usually stirring in 1 to 2 grams per liter (one to two ounces of powder per 6 gallons). This amount may seem high to people who have used Polyclar for grape wines, but kit wines take significantly more treatment to remove oxidized compounds. It requires repeated stirring over a period of hours and rapidly settles out. Then filter the wine and adjust sulfite to 50 PPM. Polyclar can diminish aroma compounds, so you may wish to do a trial on a small sample of your oxidized wine.
3. But Not Too Light
Polyclar can also indiscriminately remove polyphenolic compounds (tannins) and desirable melanoidins. For this reason it is much more damaging to red wines, and a dose can strip a brick-red wine to salmon-pink, and remove enough of the tannins to leave it flabby and soft. But a small trial will tell you if it can help the wine without stripping it too much.
It is possible to re-correct the color and flavor of a Polyclar-stripped red wine with the addition of oenocyanin (grapeskin extract) and tannin, but wines treated this way have a “manipulated” taste, and rarely age well.
WHAT’S THAT AWFUL SMELL?
Wine Smells like Matches
Your wine may have too much sulfite, which is characterized by a “burnt match” or “sulfur volcano” smell, often accompanied by a tickling in the nose. However, the true level of sulfite can’t really be determined without a proper test. Until you’ve had your wine accurately tested, don’t attempt any correction of the sulfite level. Consult your instructions for the correct sulfite level in the kit.
Minor excesses of sulfite (an extra 10 or 25 PPM) can be driven off by stirring small amounts of oxygen into the wine, effectively oxidizing the free sulfite into bound sulfite, taking it out of action. You can stir air into the wine with a spoon, rack it with plenty of splashing, or bubble air into it with a brand-new, sanitized fish tank aerator for a short period of time. As always, test, adjust and test again.
Larger amounts of sulfite (up to an extra 50 to 100 PPM) can sometimes be treated with a hydrogen peroxide addition. Hydrogen peroxide is a very potent oxidizer. In high concentration it is used as part of the fuel mixture in rocket engines, oxidizing the fuel so rapidly as to resemble an explosion. It does the same thing in wine, oxidizing the sulfite, taking it out of action.
For every 10-PPM of sulfite to be removed in 6 gallons of wine, add 4.2 ml of regular drug-store hydrogen peroxide. You must use a brand-new bottle of 3% USP-grade hydrogen peroxide, measure with a syringe to get accurate results, and above all, test before and after your adjustment.
The big problem with using hydrogen peroxide is that it’s very touchy. If your calculations are off by even a few drops, you will not only reduce the sulfite, you will also strip its protective power from the wine and oxidize it beyond redemption. Your wine will crumble to stinking brown goo before your very eyes. If this happens, the sewer is the only place to put the wine.
4. Knowing When to Give Up
In the case of massive overdoses of sulfite (in excess of 100 PPM too much) there is no answer. Hydrogen peroxide doesn’t make the sulfite disappear, it simply shifts it into another form, and too high a concentration of the bound form is not acceptable for human consumption. Again, it’s the sewer for that sorry batch of wine.
Wine Smells like Chemicals or Plastic
If you introduced any of your cleaning chemicals (chlorine, detergent and caustics, free halogen sanitizers such as iodophor) into the wine, you should discard it immediately. While small amounts of these products may or may not be harmful to your health, there is no way to be sure.
2. Equipment Taint
If you used a non-food-grade fermenter, you may have a real problem on your hands. In addition to causing odd plastic aromas in the wine, non-food-grade buckets and pails use volatile chemicals and sometimes heavy metals such as antinomy, arsenic and lead to keep the plastic pliable and soft. They may also contain UV blockers that are toxic. The alcohol in the wine will leach these out, and could seriously jeopardize your health. Discard the wine — and the buckets!
Wine Smells like Sherry
Your wine is oxidized. See the section on color problems.
Wine Smells like Rotten Eggs
1. Your Strain
Most yeast produces a small amount of hydrogen sulfide (H2S) during fermentation, producing a whiff of rotten egg. Certain yeast are famous for producing large amounts of this aroma, the Montrachet strain being particularly bad. However, this is rare in wine kits, as excess H2S is usually a symptom of low nutrients in the must, or too many grape solids — conditions that don’t apply to wine kits.
2. Air, Not Copper
If you do get this problem it can sometimes be cured by aeration, like the treatment for small amounts of excess sulfite. If it’s worse than a whiff, the fix used to be to treat the wine with copper, either in the form of metallic copper (a handful of sanitized pennies tossed in the carboy) or with a product called Cufex, which is a copper sulfate compound. The problem with this is that even in small amounts, copper is toxic to humans.
3. Germans to the Rescue
However, there is a treatment available that is both easy and safe. It is a product called “Bocksin,” which is made by a German firm. Related to the fining agent silicon dioxide (kieselsol), this product is stirred into the wine at a rate of one ounce per 6 gallons (30 ml per 23 liters). It immediately bonds to the hydrogen sulfide and removes the aroma. Because it’s formulated like silicon dioxide, it acts like a fining agent, bonding to proteins in the wine, settling out and leaving sediment. It may be necessary to rack or filter the wine after using Bocksin, but in most cases it seems to work, salvaging seemingly doomed-to-stinkiness wines with rapid ease.
4. Knowing When to Give Up
However, there will come a point where the hydrogen sulfide will chemically change to another compound called mercaptan. This compound is added to propane and natural gas to give it the distinct “skunk” aroma that alerts people to gas leaks. Once it has settled into a wine there is no treatment.
Wine Smells like Yeast
Actively fermenting wine will have a faint yeast smell, but if the wine in the carboy takes on a heavy smell like bread, you may be smelling the beginnings of autolysis.
1. Progression of Autolysis
Autolysis is the physical action of inactive yeast cells disintegrating and releasing their internal contents into the wine. Essentially, the dead yeast rots and decomposes. Because the material they release is rich in amino acids, it has a distinctive odor. The good news is that autolysis takes many months to occur at room temperature, and even longer at cool temperatures, and in any case only happens in the presence of a visible sediment of yeast.
If you follow the instructions in the kit with regards to racking, fining and stabilizing, you should never see autolysis in any of your wines. But if you miss racking a kit for an extended period of time, your wine may be vulnerable. If caught at the first sign, quick racking and sulfiting can prevent the autolysis from overwhelming the wine, but if it has already progressed to the point where it can be strongly detected as a brewer’s yeast smell, there is no cure.
Your wine is infected with Acetobacter. See the bad news in the color section.
Wine Smells like Trout or Rotting Geraniums
Just as lovely as it sounds, this problem is unfortunately not as uncommon as we’d like to see in wine kits. When it is full-fledged, this condition can wrinkle noses at one hundred yards, and once smelled is never forgotten.
1. Hexadienol: The Bad Guy
The compound hexadienol causes the odor. It is produced when lactic bacteria consume the sorbate in the wine kit. These bacteria are present wherever human beings live, and are on virtually every surface as well as being airborne. They are easily suppressed by the sulfite included in a wine kit. However, if the sulfite level falls, either through oxidation, or because the winemaker did not add the correct amount, they can infect the wine.
Normally lactic bacteria will produce low levels of off-odors, sometimes described as cheesy, mousy or musty. Most people will never notice them. However, in the presence of sorbate, which is included in wine kits as a stabilizer, they produce the stunning aroma of fermented trout and flowers. This is a terminal condition, and the wine must be discarded.
The best way to prevent this is to make sure you are adding the full amount of sulfite included in the kit. If you are adding extra rackings to the processing of the kit, or if you are storing the wine for long periods of time, make sure to top up your carboys and monitor your sulfite levels.
3. No Sulfite Means No Sorbate
Also, if you choose not to add the sulfite to your wine kit (don’t get me started on how completely naughty this is), you must not add the sorbate either, lest disaster result. Without the sulfite to suppress them, lactic acid bacteria could have a field day with your wine.
Wine Stinks when Poured
1. Bottle Stink
When young wines are put into the bottle they sometimes carry a residual aroma of fermentation, a hint of hydrogen sulfide or a slightly yeasty character. This usually dissipates with time. If you’re drinking your wine young, decanting it or swirling it in the glass will often drive off most of the aroma. If the stinkiness persists, your wine may have hydrogen sulfide or excess sulfite (see above). Also, make sure your wine is completely de-gassed before bottling. This will cut down on any off aromas carried into the bottle.
2. Mousy Wine
If some of your bottles of wine have an aroma like a wet mouse, but others seem normal, you may have a trichloranisole contamination from corks. Trichloranisole is a combination of a mold from the lignin, or fibrous part of the cork, and chlorine, used in sanitizing the corks after harvest. It’s a persistent problem in the cork industry, and one all winemakers have to live with, even if they use the highest quality corks. There is no cure but to open another bottle.
The Sunny Side of the Street
The good news in all of this is that most of these problems are actually very rare. Of the hundreds of thousands of wine kits sold every year, we see very few cases of real defects in processing. It turns out that kit winemakers are pretty savvy for the most part.
With good sanitation, accurate measurements of temperature and gravity, and detailed record-keeping, you should never see most of these problems. But if you do, don’t panic: Most of the common conditions are easily fixed. Check out your options, and if you get stuck, call your retailer. Most winemaking stores have been in business a long time, and like me they’ve seen it all. They’ll help you get back on the right track, pronto.