Thanks for the reassurance ("I'm not competing . . . ) but don't worry. Honestly I did find your initial responses off point and unwelcoming, but you fixed that. I don't carry grudges and we're good now. I have full faith that you are trying to help.
My initial ferments (years 1-4) used nutrients that contained DAP. I struggled with over-active yeast and consequent issues in the mead. Lately (years 4-7) I've migrated to organic nitrogen -- Go-Ferm initially and then Fermaid O throughout. That's helped a ton.
As I suggested earlier, I'd prefer not to do A vs B comparisons simultaneously if I can avoid it. That seems to imply that 50% of my mead will be sub-par. I'd rather try A based on my best understanding of best practice. Then if I achieve something of at least decent quality, I'll shoot for incremental improvements. But maybe my experiments are more like A now then B later if necessary.
What I can tell you for sure is:
1. Fermaid O is working better for me than any supplement including DAP. This wasn't A vs B at the same time, It was A (some DAP) previously then B (all organic) now, subsequently. I can't say that everything was exactly the same, but otherwise the two protocols were very close.
2. I'm using a yeast that is less sensitive to warm temperatures (>70 F), and I am also being careful to ferment mainly in winter when my workspace is cool (62-68 F). That has probably helped. Some of prior problems involved other yeasts and/or warmer temps (but never much worse than 72 F).
3. Confusing issues, however, is the fact that as I've made these changes I also made other changes. For example, my additions of minerals started roughly the same time as my switch to organic N. Re minerals, the main change is the addition of 300 ppm of K (Potassium MonoPhosphate or Potassium Diphosphate, not KCL) at the outset as a buffer, then K2CO3 or KHCO3 in small increments to keep pH >3.2. Of course, the initial addition of K is also an addition of Phosphate.
Yes, the two batches I mentioned were following my current protocol, which uses Go-Ferm followed by Fermaid O, but no DAP. Yes, these were two exact batches except (1) there were different honeys, one citrus, the other cranberry; and (2) there were slightly different adds of K Bicarb to manage pH because the cranberry honey was slightly less acidic. Otherwise these were identical. And yes, I did measure pH. I measure Brix at the outset, SG as needed 4-6 times, and both temperature and pH almost daily.
Your comments are compelling me to search through old documents and do new research. For example, my notes say that it was Scott Labs that recommended >300 ppm of potassium to buffer pH, so I looked for a document to support the note but I couldn't find one. On the other hand, I found this new research report. Unfortunately, the paper is behind a pay wall; but the abstract is informative (with my emphasis added):
<< Inorganic phosphate, potassium, and magnesium are key minerals required for yeast growth, metabolism, and survival, the present work investigated its impact in yeast-flavour formation using a multi-factor experimental design, which was used to generate a range of phosphorous-potassium-magnesium resulting in a 28-point D-optimal design. Samples were evaluated using HPLC (ethanol), GC–MS (aroma), and CountStar (total yeast cell). Results revealed that
yeast requires a minimal amount of inorganic phosphate, potassium, and magnesium (250, 500, and 70 mg/L, respectively) to support yeast-growth and ethanol/flavour formation. Inorganic-phosphate was important for fatty acid esters formation/short chain fatty acid (SCFA) reduction. Potassium was important in the formation of acetate esters/higher alcohols. Magnesium was the most important inorganic element for ester formation/SCFA reduction; furthermore, ethanol production is magnesium-dependent. In conclusion, inorganic phosphate, potassium and magnesium play an important role in yeast-growth, esters and higher alcohols formation; and SCFA reduction. Ethanol formation is Mg-dependent. >>