Your guide to calculate ABV, by use of a Hydrometer.
Step 1 – Take the reading of the original/starting gravity (OG/SG) BEFORE pitching the yeast and ignoring the meniscus dip, E.g. 1050 (1.050) on the hydrometer. Note it down.
Step 2 – Day 12/14 take the final gravity reading and again ignoring the meniscus dip, E.g. 1005 (1.005) Note it down.
Step 3 – take away the smaller No. (1050-1005) = 45
Step 4 – divide the answer (45) by 7.64 = 5.89 round it off to the nearest whole No. in this case it’s 5.9
Step 5 – now add to the 5.9 answer a further .5 this allows for secondary fermentation in the bottle, barrel or keg. The calculated ABV of your beer is now 6.4% - Not Bad!!
You can use this calculation for both Beer & Wine making however, because wine does not require a secondary fermentation, please ignore step 5 above.