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 complete....do 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 number

  1. 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?

  2. 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.

  1. 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 bottom?

Thanks in advance for all your help!

Reply to
Chris
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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

Reply to
ninevines

Thanks...this information is useful...

Reply to
Chris

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

Reply to
PJ

PJ But you *do* disappoint me. Go back and read what was actually said.

Reply to
frederick ploegman

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

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