Niagara Wine Wild Yeast Fermentation

[PitBull]

Our local brewshop purchases 300-gallon vats of wine juices in season (which they refrigerate) for sale to their patrons. Wine from their juice is only slightly more complicated than from a wine kit as they make “recommendations” for added sugar, yeast types, other additives, any back-sweetening, etc.

The Niagara grape grows in the Lake Erie region here in PA, and is a cross‐breed of the Concord and white Cassady grapes. And like the concord, the wine tastes almost exactly like the grape itself. This un-oaked, dry, white wine was started in October.

As per their recommendation, I mixed the must including the juice, sugar, and additives, including potassium metabifulphite. To my surprise, I awoke the next morning to a very active wild yeast fermentation. The K-Met was not old so the wild yeast must have been quite concentrated in the cold juice. I quickly mixed a double batch of EC-1118 (the recommended yeast for the dry version of the wine) starter and added it the next day. Either the competitive nature of the EC-1118 overtook the wild yeast or the wild yeast did not cause any harm, perhaps both. All has ended well, the wine is tasty albeit a bit tart. After sorbating and sulfiting, a little bit of recommended back-sweetening will be added before bottling this weekend.

Perhaps I should have sulfited just the juice rather than the whole must? ???

 

[Medsen Fey]

Well as long as it turned out well, the way you handled it was fine. In addition to the wild yeast there are all sorts of feral yeast floating around in a brewshop that could have become establish and would have been tolerant of the SO2. Whatever the case, chalk it up as a success.

 

[PitBull]

Well as long as it turned out well, the way you handled it was fine. In addition to the wild yeast there are all sorts of feral yeast floating around in a brewshop that could have become establish and would have been tolerant of the SO2. Whatever the case, chalk it up as a success.

Any suggestions on keeping it from happening in the first place? I'm hoping to make some type of dry red wine from California juice (selection to be determined) which is available a month or two before the Erie region juices. I'd rather successfully prevent the wild yeast fermentation than to successfully overcome it. The juice is dispensed directly from the closed, refrigerated tank, into my sanitized primary fermenter.

 

[dr9]

Welch's sells 100% Niagara grape juice with added vitamin C and p. metabisulfite. You could just use that juice?

 

[Medsen Fey]

Any suggestions on keeping it from happening in the first place?...I'd rather successfully prevent the wild yeast fermentation than to successfully overcome it. The juice is dispensed directly from the closed, refrigerated tank, into my sanitized primary fermenter.

Spontaneous fermentation is a common problem with any fresh juice. Folks who order fresh juice pails often find it has started fermentation when they get it. The only definitive ways to prevent it that I know of are pasteurization (not a good option) or sterile filtration (probably impractical). The other way to prevent it is to have the juice freezing cold. Then you can pitch as it warms up (a strain like EC-1118 can function well at low temp) and that should help the pitched strain take dominance right away. Sulfites can often slow down the native yeast, but not always as you have seen, and sometimes vineyards dump spent lees back out around the vines leading to sulfite tolerant strains covering the grapes.

Many folks would say that a multistrain fermentation may increase flavor and complexity, so it may be a positive.

Medsen

 

[PitBull]

Welch's sells 100% Niagara grape juice with added vitamin C and p. metabisulfite. You could just use that juice?

Yes, that would work, as long as K-met level is okay. I'm not sure of the cost of the Welch's juice, but I paid $6.50/gallon for the vineyard juice, plus about $1.50/gallon for the additional sugar needed.

Unfortunately, the wild yeast potential still would exist for the deep red California wine juices that would be available in late summer.

 

[PitBull]

Spontaneous fermentation is a common problem with any fresh juice. Folks who order fresh juice pails often find it has started fermentation when they get it. The only definitive ways to prevent it that I know of are pasteurization (not a good option) or sterile filtration (probably impractical).

Since I have a Buon Vino Mini Jet, would it be worthwhile to run the juice through the sterile (0.5 micron) filter? Or would that remove too many of the desirable qualities of the juice as well? Otherwise I guess I'll either use the cold juice method, and/or hit it right away with a double dose of yeast starter.

 

[Medsen Fey]

The usual 0.5 micron pads for the Mini Jet are nominal filters meaning they will not remove all the yeast cells (as opposed to absolute filters), so it won't prevent the problem.