Natural Yeast Tolerance

[middle_welder]

Hello, all. I'm making a five gallon batch of wild mustang grape wine using Jack Keller's old Czech recipe found at the bottom of this page.

The recipe simply calls for equal parts mustang juice / sugar water and relies solely on the yeasts that occur naturally on the grapes. I'd like to know if anyone could tell me at about what %ABV the natural yeasts should die off. I'm concerned they may either be too hardy and will make rocket fuel, or too weak and produce a weak wine. I understand there's no guaranteed tolerance (had a batch of strawberry whose Lalvin accidentally made it to 27%) but if there's a good rule of thumb I'd love to hear it. Cheers!

 

[Julie]

27% are you sure about that? Most yeast will die off around 18%

I won't depend on that recipe, I would crush the grapes and take a reading to see how much sugar you need to add, bring the sg up to 1.080 - 1.090. And take an acid text and add water to lower the acid. I believe the mustang grapes are high in acid. Then add your own yeast, I think I would go with Lavlin 1116 and let it ferment to dry, then backsweeten if you want.

 

[middle_welder]

Pretty sure, unless my readings were way way wrong. My SG was 1.082 and it finished at 0.882. The yeast I used was supposed to cash out at about 18% so needless to say I was more than surprised myself. But I digress.

I made a batch using Keller's recipe/process when I first started making wine, but in my ignorance failed to take gravity readings, so I have no way of determining the natural yeast's ABV tolerance for control. The recipe turned out fine; dry and bold, and I'd like to do it "the natural way" again but I'll be sure to have a pack of yeast on standby to restart if needed.

Fun Fact: You're right about the Mustangs being highly acidic. They'll actually blister your tongue if you wind up on the wrong vine.

 

[cmason1957]

I would be incredibly surprised if your hydrometer allows you to read 0.882, most of the ones I have seen only go as low as 0.990.

 

[middle_welder]

It's a triple scale hydrometer. The readings go from 0.800 to 1.160.

 

[jimmyjames23]

Triple scale means SG, Brix and potential ABV.

I've never seen one go below .990.
Do you have a pict?

 

[GreginND]

Sorry, with a starting gravity of 1.082 you are never going to get anything close to 27%. You are only at 20 Brix which will produce a max alcohol around 11%

 

[robie]

Wild yeast are very unpredictable until you ferment with them and a specific grape the first time. What you are doing is testing the waters, so to speak. The result could be terrible or it could be good. If you don't want to take that chance, do as Jules wrote and add your own yeast.

A lot of the recipes on Jack Keller's site are sent in from various sources. They may or may not be the best recipe. There are several on here who can help you get the most out of your mustangs.