When should alcohol be read

[Kybren]

Iv just done my first proper AG beer which I put in a PB in the shed where I normally put my beer about 3weeks ago, which hit all OG and FG I had a bottle of it earlier to try and noticed the hydrometer is barely reading any alcohol which is meant to be 5%.
My question is when should it read actual alcohol content? Iv had kits and extract brews before which im sure had alcohol by this point?
Thanks

 

[Clint]

If you say you hit og and fg the difference once calculated is your alcohol %.

 

[xozzx]

Not sure what you mean by the hydrometer not reading any alcohol? A hydrometer measures the specific gravity of a liquid (how dense it is compared to pure water). Before you add the yeast you measure the OG which is high because of all the sugar (makes the water more dense). The FG is after most of the sugar has turned into ethanol (and CO2) which is much lighter than water, thus lowering the density. As the only change to the wort is the sugar turning into ethanol then it is possible to calculate the alcohol from the difference in gravity. It is not possible to measure the alcohol (without complicated equipment) in the beer.

 

[xozzx]

The calculation is
ABV = (OG - FG) * 131.25 ABV = alcohol by volume

 

[LarryF]

Hit the calculator button at the top of the page and use the ABV calculator. Put your OG and FG in and add .2 for the secondary fermentation and there you are.

 

[Kybren]

Ah I think now reading my hydrometer I realise I had missed the word potential out which its all now making a lot more sense.
Sorry iv been a idiot

 

[Leon103]

Where on a hydrometer does it say potential

 

[Norfolk79]

If it's one of these hydrometers (the first one on the page) http://www.boomsbeat.com/articles/140533/20161011/top-best-5-wine-hydrometer-for-sale-2016.htm
then i guess the potential alcohol reading would the one taken at the start?

 

[simon12]

Does anyone know with these hydrometers could you instead of taking a OG & FG reading and donig the calculation could you just read the starting potential ABV and subtract the finishing potential ABV reading?

 

[simon12]

I think I can answer my own question by looking at the reading on the picture in the link it looks like you can.

 

[dad_of_jon]

yeah I've got one but the potential abv is not worth bothering with, it gives a ball park figure i use OG and FG then abv calculator

 

[Gunge]

Mine's got a potential alcohol scale. The clue is in the word 'potential' as it assumes every molecule of sugar being used up and probably only applicable to wine.

 

[-Bezza-]

instead of taking a OG & FG reading and donig the calculation could you just read the starting potential ABV and subtract the finishing potential ABV reading?

It's kinda the same thing isn't it, only less accurate given how hard it is to read the potential ABV scale? The maths is pretty much the same so probably doesn't save much.