I've spent a good 90 minutes trying to root up the answer to this on various wine/mead sites and am starting to doubt my ability to use search engines. So here it goes.
What is the method for calculating final alcohol percentage in a recipe such as this blueberry mead in the recipe section of this site where some of the honey is continually added at each racking?
Ok, I'll try and explain as simple as I can. If you look at the alcohol scale on your hydrometer this % is actually giving you "potential" alcohol levels. In order to determine the actual alcohol content you will need two readings. One before fermentation (OG) and one after fermentation stops (FG) You will then subtract the the Final reading from your first reading and you will have the alcohol content by volume.
An example would be if your OG gravity was 15% and your FG was 4% your final Alchohol % would be: 11%
Hope that helps
PS- I am currently fermenting that EXACT blueberry recipe that you are asking about
Central to the calculation is knowing the must volume after various steps, and the anticipated FG. While the recipe starts off with the required information, it stops short of mentioning what the must volume should be after adding the berries.
The effect of adding honey in increments later in the process (for sweetening) is most likely performed after fermentation has ended. In this case, the honey serves to dilute the existing ABV rather than add to it as there would be no expectation for additional fermentation.
My last online group brew (a Riesling pyment) used a recipe that had late honey additions that did add to the ABV, and an even later addition of concentrated Riesling juice for sweetening that served to dilute the ABV.
The calculation you seek can be performed, but it requires a level of information detail not present in the recipe you will be using... ;)
get a refractometer, I'm tellin' ya. You can do all sorts of cool calculations with a hydrometer and a refractometer. (I am assuming that mead abv calculations are similar if not the same to beer abv calculations...)
Well, without knowing the SG of the original must and honey, your in the ??? zone.
Below I used:
TastyBrew.com | Recipe Calculation
I guestimated 1/2 swapout for fruit to molasses which is most likely too high, and went with 90% AA which is most likely way too low.
So a ball park number 15%.
Samples gladly accepted. :tank:
OG 1.127 FG 1.013 ABV 14.7 % SRM 7
Yeast 90% AA
Low WOW High
OG 1.035 1.127 1.050
FG 0.098 1.013 1.012
% Weight Weight (lbs) Grain Gravity Points Color
88.9 % 16.00 Honey 112.0 4.8
11.1 % 2.00 Molasses 15.2 4.0
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