Sediment Fallout & Off-odors: Wine Wizard

Dear Wine Wizard,

I made a Concord wine about nine months ago and bottled it for Christmas. I put gelatin in it twice to remove sediment and to clear up my wine. Then I added yeast stabilizer and let it sit for four days prior to bottling. During the next nine months, I racked it off four times to be sure no sediment remained in contact with the wine. The wine has been bottled for about six weeks now and is a beautiful color and crystal clear. My problem is that once the wine is open and has been sitting with the cork back in the bottle either in the refrigerator or out on the counter, a sediment appears in the wine that looks like a very fine sand. Could you please give me some advice on what is going on?

Alan Brown
Herrodsburg, Kentucky

Wine Wizard replies: You’ve got a case of the common “tartrate fall-outs.” The “fine sand” sediment you’re seeing in your bottled Concord wine is probably small tartrate crystals — or solidified tartaric acid. I’m sure you’re wondering how, when you’ve so assiduously clarified your wine, you could wind up with sand in the bottle later. I want to say two things to start out with: 1) it happens to the best winemakers in the world (you know, the folks who get $150 for a bottle of their wine) and 2) it’s entirely natural and to be expected, so you don’t have to worry about trying to correct it if it doesn’t bother you too much.

Concord grapes — along with all other grapes — are high in tartaric acid, a natural fruit acid present in the grapes as they grow. In finished wines, tartaric acid helps your wine maintain its “pucker” and the refreshing “zing” that so many of us enjoy in red and white wines alike. Tartaric acid is often added by winemakers before a wine is fermented because sometimes the grapes (or tree fruit or berries) used to make other types of wines don’t have enough of their own natural acid.

Your finished Concord wine is full of natural, dissolved tartaric acid. The acid is part of the wine, much like sugar crystals that are dissolved in a cup of coffee. However, these tartaric acid crystals don’t always like to stay nice, dissolved and — most importantly — invisible. Temperature changes, additions or movements like bottling and filtering can change the delicate dynamics of a wine so that some of the dissolved acid will actually crystallize into a solid. Once the particles become large and heavy enough, they will fall to the bottom of the bottle where they will look like find sand, or if there is a lot of tartaric acid and it formed especially large crystals, shards of broken glass.

Temperature changes, especially cooling (like putting your leftover wine into the fridge overnight), seem to be the main culprit when the dissolved tartaric acid decides to fall out of solution. A technique many wineries employ, and one that you can try too, is “cold stabilization.” This consists of chilling your wine down (fridge temperature is fine) for a few days and letting any tartrate crystals that will form fall to the bottom. You then rack the wine off the sediment and bottle it, or continue with whatever you were going to do next. Many home winemakers and brewers keep a separate “beer and wine fridge” in which they store their kegged brew and carboys that they’re cold stabilizing. If you don’t have the luxury of this kind of appointment, you could try to make space in your own fridge and use smaller containers, such as one-gallon jugs, for this step.

The “tartrate fall-out” problem is a pretty benign one that winemakers have been dealing with ever since wine was first made from grapes. The tartrate crystals are tasteless, odorless and will do you no harm if you happen to swallow them. You’ll also notice that a similar sediment, comprised mainly of these same tartrate crystals, may form when a wine ages over the years. Again, this is entirely natural and expected with all properly cellared wines, especially reds. Wine is a complex chemical soup and the sediment that forms over time is simply something that all winemakers — and wine drinkers — must take in stride.

Dear Wine Wizard,

About a month ago I bottled my first blueberry Bordeaux. I used fresh blueberries and red Zinfandel concentrate. I adjusted the taste at bottling and it was great! The wine had a nice fruity nose, complex body and a smooth finish. For Christmas I opened a bottle to check on the aging progress. I was immediately struck by a strong solvent-like smell, something like acetone. The fruity nose I had experienced at bottling was gone. The acetone smell dispersed after a minute or so and the taste of the wine was OK, but had not improved since the bottling. Am I experiencing “bottle sickness” or something worse (TCA formation)? I appreciate your insight.

Boyce L. Clark
Baton Rouge, Louisiana

Wine Wizard replies: I’m so glad you’ve discovered the pleasures of blueberries and Zinfandel! I find that these two fruits complement each other well in Bordeaux-style red winemaking. But you also seem to be experiencing the dubious joys of an “off odor” or “spoilage” character.

Your “acetone” or “TCA” smell could have a few causes. My first suspicion with an “acetone” off-odor is that high temperatures were used during fermentation. Temperatures over, say, 90° F place stress on the yeast cells, which may then produce solvent-like aromas. These aromas may be less apparent when the wine is very young and may re-assert themselves later when the wine has had a chance for its “just fermented” character to mellow out in the bottle.

TCA is an entirely different ballgame altogether. Through a complicated biochemical transformation that, as you might imagine, is not fully understood, molds that reside in corks and winery equipment metabolize chlorine to create the swampy, sharp stinky compound known as trichloroanisole. Controlling TCA, and a host of other off compounds and smelly aromas, is mostly a matter of good sanitization. However, when you “adjusted the taste” of your wine at bottling, especially if you added any juice, honey or sugar, you could have unwittingly contributed to the formation of yet more spoilage compounds by supplying existing microorganisms with a new food source.

High fermentation temperatures and spoilage organisms are usually the main culprits of these types of odors in red wines. I find that “bottle sickness” is largely a myth or a bit of wishful thinking on the parts of less-than-careful winemakers, but it might be worth your while to store your wine in a cool, dry place and wait a month or two before cracking another bottle. If you’re lucky, your wine will have changed yet again … this time for the better.

Dear Wine Wizard,

I have been making wine and other spirits for a long time and have even been known to drink wine before its time. This year I decided to age some of my wine. I ordered oak kegs for this purpose, but am now confused. I had two options when ordering the kegs. I could get charred kegs or paraffin-lined kegs. I know that distilled spirits are aged in charred kegs, so I ordered the paraffin-lined kegs.

Now, every time I read anything about aging in oak there will be something mentioned about toasting the oak. Is this “toasting” just a sophisticated way of saying “use a charred keg for wine as well as for distilled spirits?” Please answer soon. My wine is in carboys right now and I am afraid that if I do not put it away soon I will not have any to age.

B. Copeland
Rock Hill, South Carolina

Wine Wizard replies: Charred, toasted, fired … it’s all pretty much the same. In the wine industry, as well as the distilled beverage industry, heat-treated wooden barrels and kegs are used as storage vessels in which wines and liquors are left for a certain amount of time to age. In the process of making brandy or whiskey, the distillate that comes out of the still is entirely colorless. It is actually the toasted — or charred — aging barrel that imparts a golden brown color to the beverage. Likewise, toasting methods are chosen so that the finished product will benefit from the natural aromatic compounds present in the wood. The insides of barrels to be used for distilled spirits, bourbon especially, are usually exposed to a very hot flame and will be entirely black on the inside, what some folks call a very “high toast” level. Barrels used in winemaking can be ordered from coopers at “low,” “medium” or “high” toast, and sometimes only the heads (the flat ends) of the barrels will be toasted.

In your case, I would use the “charred” oak keg (as opposed to the paraffin-lined keg). Your wine should pick up some spicy, vanilla and clove-like notes from being kept in toasted wood, assuming the supplier you’re working with recommends these barrels for wine storage. A paraffin-lined keg will only serve as a place to put your wine. The wax coating prevents the barrel from flavoring the wine, and also inhibits the supposed “micro-oxygenation” effects that wine experiences when being stored in a porous wooden container.

I would also worry about paraffin being a prime spot for spoilage organisms to hide. Plain, toasted barrels are easy to wash with hot water and sanitizing agents like citric acid and sulfur dioxide. Paraffin doesn’t hold up well to any of these things, and might create a sanitization and logistical nightmare. Furthermore, who wants chunks of paraffin floating around in their wine?

When in doubt, stick with tradition. Toasted oak is the way to go when you want the benefits of attractive storage, proper aging environment and “toasty” aromas and flavors.

Dear Wine Wizard,

Hi there! I’m a teacher of wine at the Olive Garden restaurant in Dallas, Texas. I was wondering if you could help me understand what “surely” means when referring to winemaking. Something I read said it means, “on the yeast.” I still don’t understand. I have looked in several reference books, and have yet to even locate this term let alone find a definition.

Michael Ann Williams
Dallas, Texas

Wine Wizard replies: I’m so glad you wrote with this question! How many of us have stood there baffled, not knowing what to do or where to turn, when faced with an unfamiliar wine term — usually written in another language! Well, here’s the answer to your question. What you’re describing as the word “surely” is really the French term “sur lie” (you knew it would be French, didn’t you). In French, “sur lie” (pronounced “sewr lee”) means “on the lees.” “Lees” is a general word for the gooey, gloppy, sludge-like deposit that collects on the bottom of a fermentation vessel — say, a barrel — after the yeast fermentation is done.

Let me give you a simple example of how this term applies to winemaking: A winemaker has just pressed a load of Chardonnay grapes and has siphoned the juice into a 35-gallon barrel. She then adds some yeast (to begin the process of turning the juice into wine), plugs the barrel with a fermentation lock and walks away. After about a week, the yeast will have eaten up the sugar in the grape juice and transformed it into ethyl alcohol. Once the bubbling action of the fermentation stops, we’re left with what we can now call “wine,” plus a sediment of fine grape particulates and dead yeast cells that we call the “lees.” If we don’t “rack” the wine (siphon it off the solids at the bottom) immediately after fermentation into a clean barrel and instead let the new wine just sit there “on the lees”, then we are aging the wine “sur lies.”

Aging a wine on the lees is traditionally used in Chardonnay production (though I’ve seen it in the making of Sauvignon Blanc, Chenin Blanc and Gewürztraminer, all white wines). Many winemakers feel it gives the wines more mouthfeel, body, and aromatic complexity. The dead yeast cells break down over time, releasing amino acids, proteins and other biological compounds into the wine. A former employer of mine would even stick a stainless steel rod into each barrel of Chardonnay as it aged “sur lies” and stir up this sediment, further enhancing the contact that the lees had with the wine in the barrel. He felt that this traditional French technique greatly enhanced the texture of his wines and imparted them with a richness not attainable by any other methods. If you work in the restaurant business you might appreciate the fact that “sur lies” aging, usually accompanied by barrel stirring, is a time-consuming process and can contribute to the quality — and the price — of the bottles of wine you might be serving.

Do you have a burning question for the Wine Wizard? If so, e-mail: [email protected].