Before you start into the actual recipes themselves, it is best to have a quick lesson in the basic brewing terminology and calculations that you will use.
Specific Gravity (S.G.) – (Also known as Original Gravity – OG) This is used to determine how much sugar is present in the Must/Mead. The higher the SG, the more sugar is present. As the yeast eat the sugar and produce alcohol, the SG drops. This is also measured in Baumé and Brix (see Appendix 6 for the relationship between the three).
Final Gravity (F.G.) – The measurement of the specific gravity when all fermentation has ceased. The lowest that can be reached is 0.990.
Alcohol by Volume (ABV) – The amount of alcohol in your Mead, given as a percentage of the total volume. Most wines are around the 11% to 12% ABV, but it is possible to ferment up to 20% to 22%.
Calculating the %ABV – A very basic formula for calculating the ABV from the SG and FG measurements is:
% ABV = 133 * (SG – FG)
Example: SG = 1.100
FG = 1.010
%ABV = 12%
An easier way is to use the chart in Appendix 6. Find the potential ABV (p-ABV) for your SG and your FG, subtract the smaller from the larger, and the resultant is the final %ABV.
Example: p-ABV for SG of 1.100 = 13.2%
p-ABV for FG of 1.010 = 1.3%
%ABV = 13.2% – 1.3% = 11.9%
pH or Acidity – The amount of acid in your Must will determine the health of the yeast. A solution of honey in water will usually have a natural pH of around 3.7 to 4.6. The optimal pH for yeast is around 3.7 for best results.
Acid Blend – This is a blend of various natural acids, usually in crystalline form, that can be used to lower the pH in your Mead. Acid is an important part of balancing the sweetness of a Mead, so it should only be added once fermentation has ceased if it is determined the Mead is too sweet. It can also be added if fermentation is slow due to a pH above 4.6, but use sparingly.
Sugar Break – A term used to describe the point where a specific amount of the fermentables have been used up. There are two important ones to note: the 1/3 sugar break (1/3 of the fermentables have been fermented to alcohol), and the 2/3 sugar break (2/3 of the fermentables have been fermented to alcohol). These two points are usually when additional nutrients are added, if needed. Example: if the starting gravity of your Must is 1.120 (28 Brix), the 1/3 sugar break will be when the gravity reaches 1.080 (19.2 Brix). It is at these points that nutrient additions such as Fermaid K, yeast energizer etc. are usually added. Recommended dosage is 1 teaspoon (5 grams) at each sugar break.
Lag Phase/Exponential Growth Phase/Fermentation Phase – These are terms used to describe the life-cycle of the yeast and will be explained in Chapter 10.
Krausen – The foamy head that appears during the early stages of fermentation. It usually disappears after a couple of days.