working out ABV%

[brewjohn]

in W.H.T.Tayleurs book on brewing ( Penguin 1976) he mentions a method of working out the ABV by the ingredients used. He states 1 LB of DME gives 5% per gal and 1 lb of LME4% per gal and 1lb of white sugar 5%. So a brew made with 1lb sugar and 5 lb of DME would work out ..... sugar X 5 = 5% and malt X 5 = 25% total 30%. Divde this by 5 for a 5 gal brew and its a brew of 6 %. if a 4 gal brew its divide by 4 = 7.5 %. I would have thought that extract would not be 100% fermentable and would give a lower figure than white sugar would.Any thoughts on this.

[OldSpeckledBadger]

Of the three only sugar is 100% fermentable and that will give the highest alcohol content. Next will be DME and lastly LME, which is about 20% water. If he can't get that right you have to wonder what other gaffs are in the book. Sounds like a good candidate for the recycling bin.

[brewjohn]

i think I will stick to using the OG and the FG. I bought the books in my early days at the same time as Ken Shales books. Things have moved on since those days and brewing is a lot more professional !