Alcohol content

I have a few questions on this subject:
1. How can you determine actual alcohol content from PA readings? I
understand that you need to take a reading before you add the yeast,
and before you rack, and once again when secondary fermentation is you just subtract the numbers and then multiply by .74?
There was a post on the subject, but I was a little confused by the
2. I have a few bottles of must that I started in may, but did not
take hydrometer readings beforehand....will I be able to determine
alcohol content on these, or is all lost?
3. What are some recommended PA readings to have before adding yeast?
I have heard that if your PA is too low, the wine will not keep well,
and if it is >14 then the excess sugar can actually kill the yeast.
4. Can sugar be added later on in secondary fermentation to raise PA
if it is too low? If so, what is the best way to do this without
disturbing the must and without having all the sugar sink to the
Thanks in advance for all your help!
Reply to
The only two numbers you need at the starting SG and ending SG. Subtract the latter from the former, and divide by .736. Example:
Starting SG: 1.092 Finishing SG: .995 1.092 - .995 = .097 .097 / .736 = .13179 or 13.18% ABV
Probably not. The only way is with a vinometer, an inexpensive (and frustrating to use IMHO) glass measuring tool to measure alcohol in a *dry* wine.
ABV needs to be at least 10% as a general rule, and too high can taste 'hot' or overpowering depending on the type of wine. Yes, it can also stifle yeast at a certain point. Every strain is different. Start with 1.090 as a *very* general 'safe' number.
Yes, sure it can. The way I would do it is to grab about a cup or two of must with a wine thief and heat it in a saucepan, not anywhere near boiling - just warm. Dissolve the sugar in there, then add back to the must. There are calculations you can do to get an estimate of how much sugar to add to a given volume of must to obtain a desired SG.
Roger Quinta do Placer
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"frederick ploegman" wrote in message ...
Frederick, Hate to disappoint you but - I have pushed wines to over 20% abv. I have brewed beers that run in the 16% range (barleywine). You say the max is 12.4% - there are many commercial wines on the market in the 15 -16% range. Excellent wines, I might add. Please state your sources for your information. I'd love to know how I broke all the rules. HTH, PJ
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He wrote «the *maximum* PA for an OG of 1.092 is ~12.4%ABV».
This is quite different... although I am not saying it is absolutely true or not true!
Reply to
Guy, You are correct - however - Please explain to this stupid one - How is that "quite different"??
I'm thinking: PA = Potential alcohol OG = Original Gravity ABV = Alcohol by volume
I get (now) what he is driving at. A very specific gravity and it's resulting abv. I was mistaken in reading the statement he made - However, I still disagree with his 'Assumption' that the max would be his 12.4%... He is basing his calc on a final gravity of 1.000. This is a failure to take into consideration that alcohol in solution with water can have a gravity significantly below 1.000 and thusly a higher abv.. As I requested - Show me sources.. I would love to learn more. I might be old but I'm willing to learn.
PJ - The old one..
"Guy" wrote in message ...
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Hi PJ My apologies also. There really was no need for my short tempered answer. Sorry.
I have often seen the formula that Roger is using quoted in many "sources". Even CJJ Berry uses it in his book(s). But the fact is that this formula does not work. It fails to consider the shift in the reference point caused by the alcohol. Try to look at it this way. The chart that is rolled up and glued to the inside of your hydrometer is predicated on the fact that all of the scales relate to a specific reference point (SG 1.000). By taking an OG and reading the PA scale, we estimate the maximum amount of alcohol that can be produced by that must. The *only* thing that can increase that amount of alcohol is to add more sugar. Since subsequent SG readings do not increase the amount of sugar available, we can not have more alcohol in the finished wine than the original PA indicated, no matter how far the alcohol has shifted the reference point. Make sense ?? Jack Keller has a rather nice explanation on his "Hydrometer" page. HTH
Reply to
frederick ploegman
Frederick, Accepted but not needed or solicited. I get crotchety often.. It's in my nature I guess. Your reference to Jack Keller's information was very good. Thanks. I've read the entire site before, printed most of it. After re-reading the hydrometer section online again, I have a better understanding. I'm still a little confused, but that's ok too. I think a lot of my confusion comes from dealing with higher alcohol products. They generally range from 18% through 96±% abv. Instrumentation and calculations are quite different.
I really appreciate your reply. Thanks..! PJ
"frederick ploegman" wrote in message ...
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