After reading a recent article in WineMaker about using a pump to transfer wine, I put together my own pumping system. My question pertains to the possible negative effect of the wine going through brass fittings in the tubing. It only takes about four minutes to transfer the wine, but it all passes through one brass reduction fitting along the way. I would have preferred to incorporate a stainless steel fitting, but I haven’t been able to find one. Anyway, any guidance you can send along would be appreciated. (P.S., in the photo (see above), that handsome young guy pouring grapes into the hopper is my older son, also named Peter . . . as is his son.)
You might be encouraged to know that brass fittings have a long and storied history in winemaking. In fact, if you travel the back roads of Europe and poke your head into the cellars, garages and barns of many family wineries, you’ll notice quite a few brass spigots, tubing connectors, reducers and spouts around. The metal is easy to work, affordable and easy to locate. In places like the Rhône Valley or Bordeaux, however, things might be more modernized with a bit more stainless steel. This is because stainless steel is just a better all-around winemaking metal.
Brass is softer than stainless steel, so it can pit and scratch more over time, which can make cleaning more difficult. It also will lose its threads faster and so is more prone to leaks with each harvest season. It can really take a beating if you drop a fitting on the floor. Stainless steel just doesn’t have the structural issues that brass does.
The biggest negative in using brass for winemaking purposes, in my opinion, is its tendency to be soluble in wine and how hard it is for us to predict how much might or might not leach into our batches during normal use. Brass fittings can be better for higher pH liquids like beer or sea water, but the acidity of wine tends to make it a great solvent.
Now, a little copper (since brass is an alloy of copper and zinc in varying percentages) is good for wine, right? Sometimes yes, we do add copper sulfate (CUSO4) to wine to help with sulfide issues (hydrogen sulfide smells like rotten eggs and is a common fermentation and young wine defect). I won’t kill you with the chemistry, but the elemental copper in copper sulfate binds up with the sulfur-containing compounds, yielding the product less-smelly. Sometimes if you make the addition early enough and the level of your stinky compound is low enough, a copper sulfate treatment can make your problem go away entirely.
One problem with copper, and by extension, brass, is that residual copper in large doses is poisonous. The U.S. legal limit for residual copper (as copper, not CUSO4, which is only 25.47% copper) in wine is 0.5 ppm. Excess copper can also lead to a visual defect called “copper casse,” which is a fancy way of saying “haze.” Copper can complex with proteins in wine, leading to a protein-copper haze that is difficult to remove, even with a bentonite fining. Excess copper can also be a catalyst for oxidation, increasing the chances of encountering oxidative off-aromas and off-colors in wines. Because of these dangers, it’s best to add copper in a measurable amount, where you are sure you can keep the residual copper content of your wine well under the legal level and under levels where it’ll be in chemical excess and free to participate in all of those undesirable reactions.
Because brass can contain widely varying amounts of copper, anywhere from 50%–70%, and because leaching depends on wine pH and contact time, it’s really hard to judge how much copper might find its way into your wine through the use of a brass fitting. In addition, brass can also contain significant amounts of lead, or up to 2%. Since you might not know the lead content of your brass, I’d say it’s the very safest to stick with stainless steel for winemaking.
As for stainless steel fittings, check for suppliers among WineMaker advertisers (there is a directory of advertisers in this issue on page 70). I’ve personally had good luck with the following two equipment websites, or similarly research other vendors by visiting the Directory/Buyer’s Guide tab at Wines & Vines magazine.
• The Compleat Winemaker: www.tcw-web.com
• WE Winery Equipment Ltd. www.winery-equipment.com
• Wines & Vines magazine: www.winesandvines.com
I am new to homemade winemaking and I want to begin making Port-style wines. I have looked on winemakermag.com for information about Ports and have learned a lot. As far as fortification, do you always have to add distilled spirits or can you actually get to the higher alcohol content by continuously feeding the wine sugar until it reaches that appropriate level and then add the sweetness at the end if needed?
Welcome to the wonderful world of fortified winemaking! Making Port-style dessert wines is really fun.
One of the side benefits of making these types of wines is that fortified wines are typically more shelf-stable than other table wines because its high sugar and alcohol levels (typically 6–9% and 18–21% respectively) helps protect it both from oxidation and microbial spoilage shenanigans. This means you can open a bottle, sip a glass or two and simply cork it up and put it back on the shelf for a few days or weeks without too many ill-effects (to the wine, I mean!). For home winemakers and those new to winemaking, fortified wines can be more forgiving for a similar reason — because they are all about the power of the fruit, sugar and booze it means no one will notice as much if your acid level isn’t perfectly adjusted, if you over-oaked it or if you have too much or too little tannin. They are not exactly “finesse” wines the way, say a 13.8% Russian River Pinot Noir would be.
A simple procedure for a grape-based Port-style wine would include the following: inoculate 23–26 °Brix red grapes with a neutral-aroma yeast. When Brix of your normal fermentation reaches 10–12, begin “feeding” the fermentation alcohol to arrest the fermentation, mixing the must almost continually in order to get a good distribution of the added alcohol throughout your fermenter. Brandy (distilled wine, 80 proof/40% alcohol) is often added to grape Ports, while fruit-based Ports often rely on neutral grape spirits or other aromatically-neutral alcohol so the fruit flavors and aromas can shine through. I know many home producers use Everclear as it has a high alcohol content (151 Proof/75% alcohol in some states, 190 proof/95% alcohol in others) and no other flavor or aroma. For fruit Ports, I personally like to use neutral spirits to let the fruit shine through, and for grape-based Ports, I think using oak-aged spirits can bring a benefit — it’s up to you as the winemaker, however, to decide what works best in your Port.
Depending on your yeast strain’s alcohol tolerance, the yeast will begin to lose steam as the alcohol level rises beyond what they can tolerate, typically 14% alcohol and above. Essentially, the rising alcohol level will kill your yeast cells and you’ll be left with a wine that has un-fermented sugar between 6–9% and hopefully an alcohol content of 18–21%. I recommend aging the stopped, sweet and alcoholic wine in a neutral oak barrel (or in a carboy or keg with French oak chips if you don’t have a barrel) for at least six months before thinking about bottling. Some fruit Ports can be ready faster than grape-based wines, which often need quite a bit of time — at least 10 months — to mellow out. I like to give fortified wines at least 18 months bulk aging to let them throw deposits and precipitates. Because of the higher alcohol content, proteins and other material will tend to come out of solution over time.
As you might imagine, there are many variables that will dictate what the final alcohol level and residual sugar level will be. The ability of your yeast to resist alcohol, your initial Brix and the alcohol level of your added spirit will all contribute to the algebra. When I worked at Bonny Doon, I remember building spreadsheet models where I would plug all of that data in to predict my final sugar and alcohol content, as well as when it was predicted my fermentation would stop. Whew, you can geek out on that stuff!
If you’ve been keeping up with the math, here, you’ll understand that you can’t just feed your way to fortified. Even by using alcohol-tolerant yeast and step-wise sugar additions, your yeast will peter out at no higher than 15.5% alcohol . . . almost high enough to be fortified, but not quite. You’ll just have an alcoholic wine with some residual sugar. To really smell, age and drink like a Port-style dessert wine, you really want your alcohol to be a little higher.
For further reading, check out the column that Joe O’Neal wrote on fruit Port back in 2004: www.winemakermag.com/component/resource/article/313