Superyeast x-press - Can it really ferment 20% ABV?

[garymc]

So it looks like about 22 pounds of sugar in 6.5 gallons of juice gets around 20% abv. But since you have to add the sugar in parts you don't ever see a sg with all the sugar present and unconverted. This would be fine since 22 pounds is 22 pounds, but part of that 22 pounds is the sugar that was already present in the juice naturally. Does anybody have a range of equivalent ounces of sugar per gallon that might be found in muscadine (or other grape) juice?

 

[mmadmikes1]

If you check sg before adding more sugar and after you just keep adding difference to starting number then at end calculate away

 

[grapeman]

Does anybody have a range of equivalent ounces of sugar per gallon that might be found in muscadine (or other grape) juice?

Check the SG of the juice prior to fermentation and use the chart I showed the link to on the last page from Jack Keller. That will tell you how many ounces of sugar are in that specific gravity.

 

[garymc]

That's what I thought.

 

[BigMac]

Here is an excerpt from the link sent by Grapeman which I think this summarizes our discussions.
"Accurate alcohol content cannot be calculated using a hydrometer alone because the actual S.G. of pure alcohol is 0.792, not 0.990 as most hydrometers read. However, if you accurately measured your must's S.G. before yeast was introduced and fermented it to an S.G. of 0.990, racking as required, your calculation should be accurate to 1%."

I think the conclusion is that the Superyeast A-Press Yeast, Sugar:ABV% ratio information is incorrect.

Thanks to all for the dialog.

Fermentation has kicked off. I am going to slowly add sugar up to 22lbs and additional nutrient. In a while I will let you know what the final ABV turns out to be.

Jim

 

[BigMac]

test Test

test Test Test

 

[seth8530]

Extrapolating data from the sugar vs potential alcohol data ( this can be a little lossy) I get that we need 3.25 lbs of sugar per gallon to hit 20% abv.. or 21.125lb for 6.5 gallons. However, I'm not sure if the table I grabbed the data from accounts for volume displacement of sugar or not.