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?
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.