Advice on discovering alc/vol?

[Feygan]

Ok so I have the first batch of ginger beer soon to become ready, however I have no way of knowing the rough alcohol content. (other than the drink till you sink scale :P )

So is there a way to get a rough estimate of a brew?


Here's a quick recipe if it helps.

Half pint of water, with half a tspoon of yeast, 2 tspoons of sugar and 1 tspoon of ground ginger. Then add 1 tspoon of ginger and 1 tspoons of sugar each day for 7 days.
After a week, add 1lb of sugar to a pint of boiling water along with the juice of two lemons, the "plant" is then strained into this along with 7 pints of water before being bottled for 3-4 weeks.

[9ball]

Right, going that it's about 1 pound of sugar in about 1 gallon of liquid, if all the sugar was fermented it would be about 4.5-5%. I'm assuming it won't all get fermented in ginger beer so something like 3%ish?
A good rough guide is 5% abv for every pound of sugar in the gallon, or 4.5% for every pound of sugar added to the gallon.

And watch out for exploding ginger beer bottles!

[Jandra]

If you brew more often it might be worth buying a vinometer. It's a little glass device which allows you to measure the alcohol percentage within 0.5% exact in the finished brew. Should cost you around 3 quid (bought mine for about € 5 in the Netherlands).
Jandra

[QuakerBear]

Right, I'm going to abit vague but here goes.

I've seen Mr. QuakerBear putting a plastic stick thingie in a bucket of his wine. I think it can tell you how much alcohol is in there by how it floats. He got it from a home brew shop.

But then maybe I've got compleatly the wrong end of the stick.... Good job he makes the wine and not me.

[9ball]

The plastic stick thingy is a hydrometer, or vinometer.
These measure the specific gravity of a liquid, when sugar is in a liquid it makes it heavier and so it has a higher specific gravity - and the little hydrometer floats up higher on the surface. As the sugar is fermented the S.G drops down as there is less sugar in the liquid and the hydrometer will sink further down. So if you measure the initial S.G. and the S.G after fermentation you should be able to calculate the strength of your beer or wine. Once something has finished fermenting it can't tell you how strong it is - as you need a reading of the original must.
My one is quite handy because as well as the specific gravities on the scale it has a potential alcohol gauge and also a bit to tell you if the wine is sweet medium or dry and ready to bottle. Handy things and worth getting one if you are making wine, and pretty useful for beers and ales.

[Cheezy]

Exactly right. If you haven't got a hydrometer the other way is to work out the percentage sugar.

For example if you make 5 litres of liquid(nearly a gallon) with 500g (neck end of a Lb) of sugar that is a sugar content of 10%. If you use a high tolerence yeast and convert all the sugar to alcohol , the best you can expect is 50% conversion, so 5% alcohol.

The problem comes when you add fruits and cereals which contain natural sugar, this is when you need to check the origianl gravity (O.G), then check the final (or fermented) gravity (F.G) and that will give you the alcohol by volume (A.B.V)

The way to dothis is you measure the liquid prior to yeast addition (O.G) at the specified temperature which the hydrometer is rated at (usually 23'C i.e room temp). After fermentation you measure again. this is the F.G, subtact F.G from O.G and times by 131 this equals ABV

example

Pure juice cider should have a O.G of around 1.070 . You should brew to at least 1.005 prior to bottling (to ensure no explosions)

1.070 - 1.005 = 0.065 x 131 = 8.5% whoohoo some good ol' stuff.

If by some mirical your apple wine is OK, then my rule of thumb is 1 bag of sugar (1Kg) per gallon, disolve and pitch in a wine yeast. Bob's yer uncle.

If your apple water is a little iffy, but not revolting, you could try and rescue it by adding a crushed campden tablet per gallon , leave over night then pitch the yeast.