The Initial Problem
I came across a barrel of wine contaminated with TCA recently. Not a terrible case, but it was present in the wine. Oddly enough, it was one barrel in a five barrel lot, all of which were new barrels. I have heard of barrel contamination before, but never seen it myself. I looked into TCA reducing pads that Gusmer used to sell, but they are no longer available. There is a company in California, Heyes Filtration which sells another brand of pads, but they are very expensive, about $350 for a pack of 10, If I remember correctly. So I tried another route.
Supposedly TCA is fat soluble, so whole milk is apparently effective at removal. The TTB limits the addition of milk to a maximum of 2mL/L (2000ppm), which is a pretty big addition.I have used milk before to fine wines before (not for TCA), usually in about a 250ppm range, so for this moderate TCA level I decided to start with 500 and 1000ppm whole milk additions.
Also, though it is not officially allowed by the TTB, polyethelene (plastic wrap) is effective at adsorbing TCA. I have heard that you must use large amounts (“a pallet of plastic wrap slipped off the forklift and fell in the tank”). But how much is a lot, and how would I actually perform the trial. One roll from the local grocery store contains 100 feet of wrap. With the roll being 1 foot wide, that means that 1 box contains 100 feet^2 of wrap. 10 feet^2 in per gallon would result in using 6 rolls of wrap to treat this barrel. So I decided to try 10 (6 rolls), 20 (12 rolls) and 40 feet^2 per gallon (24 rolls) for my initial fining trial.
10 feet^2 per gallon of wrap = 10 feet per 3.785 L = 1 foot per 378.5 mls, and 378.5 is pretty damn close to 375mls, a half bottle. That’s great, because I wanted to use a 375 for the trial bottles, however I realized that that volume of wine and that amount of wrap would not fit in the same bottle, so I decided to keep it simple, and use half that volume, 190mls.
I took the correct amount of wrap and cut it into roughly 1 inch strips and pushed each strip into the bottle. I let the wine sit in the bottle for about an hour and then tasted. Surprisingly, even the 40 feet^2/gallon rate still showed a large amount of cork taint. This was 24 rolls in one barrel! So i decided to look at higher rates, 50 and 100 feet^2/gallon, 1/2 and one roll per gallon! Talk about needing to use a very high rate.
10 feet^2/gal = 0.5 feet^2/190mls = 6 rolls/barrel 20 feet^2/gal = 1 feet^2/190mls = 12 rolls/barrel 40 feet^2/gal = 2 feet^2/190mls = 24 rolls/barrel 50 feet^2/gal = 2.5 feet^2/190mls = 30 rolls/barrel 100 feet^2/gal = 5 feet^2/190mls = 60 rolls/barrel
The Results of the Final Tastings
For the final tasting we looked at a control, 500 and 1000ppm of whole milk, and 1/2 and 1 roll of plastic wrap per gallon of wine. Consensus was that both milk levels lessened the sensory effect of TCA but did not eliminate it. At the 1000ppm level it definitely stripped all positive qualities too. We felt similarly about the plastic wrap, at the higher level seemed to eliminate all traces of TCA, however both rates stripped all positive characteristics from the wine. Additionally, the cost on the high rate of 1 roll per gallon would probably be over $100, making the cost of the TCA removal filter pads look much more attractive. Hopefully removing most of the taint will be sufficient, hopefully it beats the alternative.
In the end we decided to treat the wine with the 500ppm milk and use about 18 rolls of plastic wrap after racking the wine off the milk lees. If I were to do this again, I would definitely look at half and half or cream to see if a higher ratio of fat to protein would improve its effectiveness. I will give an update when I taste the treated wine.