Thanks all for the advice. Too late, I’ve already dumped it as according to the hydrometer it was at zero alcohol and I thought that it hadn’t fermented. I have a lot to learn. Onto the second attempt and I’ll keep the temperature down. Keep you posted. This time a Coopers Lager. Cheers.
That "Zero Alcohol" is a bit misleading!
The scale should be read as potential alcohol, if you started with a potential of 5 and finished at 0 you have made 5%.
In wine making and with some super dry beers you can finish in the negative numbers say -1, in which case the amount of alcohol you made would be 5-(-1) = 6% (a negative minus a negative is a positive, try it on a calculator).
Most home brewers use the S.G. (Specific Gravity) scale. Which is simply how many times the solution is denser than water.
So water is 1.000 times as heavy as water, beer wort us
usually somewhere between 1.040 and 1.060 times as heavy as the same amount of water.
A litre of water would weigh 1.000g or 1kg. a litre of wort usually between 1040g and 1060g (1.04-1.06kg/L)
As the yeast east sugars in the wort, it converts them into nearly equal amounts of Carbon Dioxide and Alcohol, most of the CO2 escapes (bubbling airlocks) loosing mass, leaving the alcohol which less dense than water so the SG falls.
Using the SG scale you can calculate the amount of alcohol you have made by comparing the change in gravity, we use a short hand to make the calculations easier and talk about
Points treating the numbers after the decimal point as if they were whole numbers, 1.040 would be called 40 points, 1.060, 60 points...
If you started at 1.050 (50 points) and finished at 1.010 (10points), you have had a change of 40 points
40 points divided by 7.5 gives you the alcohol content 40/7.5 = 5.33%
There are several ways to measure the amount of Extract (everything dissolved in the wort) and several scales used to report this information, at this stage probably best to stick to SG.
The other useful information you can get by measuring density is to know when fermentation is complete, take a gravity reading, wait 24 hours, take another reading. If the gravity is stable (and around where you would expect it to be), you should be good to bottle.
If there is any change in the SG, wait another day or two and take a reading - in any case a stable reading over 24 hours is what you are looking for.
Using the SG method, or the % alcohol scale on the same hydrometer will tell you the same thing - in either case you really do need to take a starting gravity reading (one before you add the yeast).
Just another couple of points that might help, the two things a kit brewer can do to really improve your beer are: -
Use better yeast - get one from a good home brew shop that suits the style of beer you are making.
Get control of your temperature - a small second hand fridge with and STC 1000 (or similar) and a small fan will help you brew more consistent and better tasting beer all year round.
Neither will cost you a bomb and you will be making better beer.
Mark