Foregoing Sulfating Must, Competitive Factor Neutral

[Kitchen]

When using an yeast with a competitive factor active, like EC-1118 and D-47, I have been foregoing sulfating the must before fermentation with the opinion that the active commercial strain will kill most of what else is in there. As soon as fermentation is over, I would sulfate the wine/mead to the correct levels. My thought in doing this is to try and limit the total SO2 introduced to the wine/mead throughout the entire process.

I am thinking about starting to do this with yeasts that have a competitive factor neutral, and just making sure to fully inoculate the must with the commercial strain.

Any thoughts?

What about doing this with a yeast that has a competitive factor sensitive? Would wild yeasts already in the must produce enough toxins to kill a commercial strain with a sensitive factor?

Thanks, Joe

 

[CDrew]

This last year, I started sulfiting less at the start. Previously I've aimed for 40 ppm and this year 20 ppm,on the theory that the grapes were very fresh and clean(I picked them from the vine!) and that I was really trying to kill bacteria, which I believe are more sensitive to SO2 than most yeasts. Not 100% sure, but that was my thinking. I had no fermentation problems with any wine in 2020.

When we add a 1gm per gallon amount of yeast, that's probably hundreds or thousands of times the population of wild yeast and so can become dominant even if some of the natives have killer factor. I've also started doing the "epic starter" routine which likely pushes up the inoculation numbers even further. Epic Starter youTube link

The one commercial ferment I'e seen pitched there was no sulfiting going on. Crushed grapes came out of the crusher and were pumped into a 3000 gallon tank. Then a guy went up a ladder and dumped in a 2.5Kg bag of dry yeast (Red Star Premier Cuvee-I asked). There was no more to it than that. I thought the yeast choice was surprising too, but that's what they used.

Will follow this to see what others think.

 

[Ajmassa]

i’ve skipped adding so2 at crush many times. As long as the fruit was healthy and inoculating w/in 2 days then not much reason for so2. The times i did add some was only targeting 25ppm.
my 2 cents- Most cultured yeasts i’ll ever be using will easily dominate at 1g/gal dosage. Not sure which yeasts wouldn’t tbh. The time i did a natural ferment i think it took almost 4 days to really get going with a skins cap.

I skip so2 at crush mainly to aid the malolactic bacteria. Lowering my total so2 is just a nice byproduct- but not a driving factor. And even if it’s a “killer negative” strain and a strong native yeast the 1g/gal dosage probably removes the issue altogether.

variables that might push me to add so2 at crush could be:
-lowering yeast dosage
-stretching the time from crush till inoculation
-extra high temps
-unhealthy looking fruit
- extra sensitive yeast

*Im unaware of which commonly used yeasts are extra sensitive. And I’m actually surprised the “killer factor” isn’t a more common stat provided. I can only deduce it’s because when put up against native yeast at 1g/gal it won’t matter.

 

[Rice_Guy]

You are playing a numbers game, and the odds of good results are in your favor. . .
. . . most of the month the girlfriend doesn’t get pregnant, but then once and a while she does and then , , having a wild wine can be quite enjoyable too

wine is a food preservation system with several fences;
low pH
reduced oxygen/ reductive environment
part of the reductive metabolism is that yeast make their own SO2
high sugar
moderate alcohol level

Our goal in inoculating is to quickly “improve” the environment and having 5% alcohol (beer) is as good a fence to keep bacteria out as the SO2 is.