What is the optimum pH for a sweet mead?
I also have had a lifeless mead that needed acid blend but I am wondering if there is another way besides guessing? Adjusting the pH by using acid blend could take out the guesswork.
I don’t think there is a standard optimum pH. The optimum pH is a function of the sweetness, amount of tannins, and type of acids used. Zymurgy and last year’s AHA conference seminars, all of which can be viewed or listened to on this site, included an article/seminar about post-fermentation fixes like acidity corrections.
I think the main thing is the flavor produced by the acidity of the finished mead. If you are diluting with an alkaline water when making up the must, then a portion of that yeast’s acid production will be consumed by the alkalinity. I don’t know if using a low alkalinity water like RO or distilled is an advantage or not in mead making.
Also the pH of mead tends to be quite low at least initially because honey contains a lot of gluconic acid, which is derived from glucose I believe. Gluconic acid is like phosphoric acid in that it provides a watery acidity. Acid blend uses acids that have a sharp, lingering character. It is somewhat likely that adding acid blend may not change the pH much, but it has a big impact on flavor.