GrapeCrafter

Clark,
We have two barrels of Zin from 2007 that will not finish. We are looking for suggestions as to how to best get this wine to finish without damaging it in the process. The grapes were a bit hot when we got them at 26 brix, maybe a bit higher. The first yeast we used was VQ15. We used nutrients and as such did not get any H2S in the process. The second yeast we used was Uvaferm 43. Neither of these were able to convert all the sugar. I cannot say what the residual amount is...but will guess it is under 1%. We have acquired some Encapsulated Wine Yeast - ProRestart QA23 but not used it as of yet. We can always blend the Zin down and may have to do that in the end but we would prefer to get the Zin as dry as possible without damaging it before having to make that decision. We are looking for any other suggestions before we make any decisions. Any thoughts or suggestions would be greatly welcomed.

Dear George:

There are four categories of stuck fermentations: High alcohol, high VA, nutrient deficiencies and toxins. Most fall into the first category, and if your Zin came in at an initial 26 brix, it was probably really 28 after soakout, resulting in a finished alcohol of 16.8 when dry.

I'm assuming this is a commercial lot of some normal size, worth investing in. The first thing we need is numbers on alcohol, sugar and VA. If you really are stuck, the normal procedure would be to dealc down to below 13% and reinoculate using Superchamp or similar highly vigorous yeast according to the Vinquiry protocol. If VA is above 0.06, you might want to adjust that at the same time.

I'm alarmed however that you don't know the RS. How, then, do you know it's really stuck? You have a fair chance to get to dryness merely by keeping it warm and monitoring its progress with a weekly enzymatic glucose + fructose. Progress may be slow, but precise numbers from such an assay could give you cause to just bide your time or to take decisive action.

George
Clark's guess as to your real starting Brix seems reasonable. I have made many lots of Zin that acted like yours. If you want to start that ripe, you have to be prepared for the result. It has taken many of my Zins eighteen months or more to complete fermentation. The big question is when to add SO2 and how much to add. My advice is to monitor the wine closely, keep it at 65F if you can, add .5 ppm molecular SO2 once fermentation seems at a standstill, and be patient. Enzymatic analysis is informative, but it may not be all that useful, as I doubt that particular wine will ever go totally dry. It might be expecting too much to demand absolute dryness, and you may not need it to make a balanced wine, depending on the alcohol and acidity. What you are really after is balance and stability- so you can bottle it. You can also expect elevated VA in the range of .8 to .9 g/l before you're finished, but that's just part of the deal, and not necessarily the kiss of death. These are just my opinions, you would no doubt benefit from others. As you can tell, I'm a fan of individualistic wines, not so much a fan of wine "making". If dryness is important to you, plan your next vintage with that in mind, pick at lower Brix, and water the must to below 25 if necessary. That's some exciting winemaking going on there- if one can hack it.

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