It says in the DMT handbook that the pH should be 4 when doing an acid cook of MHRB. Isn't it ok if it goes down to pH 2-3. Does that matter?

It's fine if it goes lower, the molecule can tolerate the low and high pH extremes without degrading, afaik. The BLAB tek calls for soaking your mhrb in straight vinegar for days, which is a pH of ~2.5 (if I remember correctly) and it yields great consistently, so there's a real world example of the low pH not adversely effecting an extraction.

This has been mentioned several times by professional chemists here:

Though there are other reasons for lowering or raising the pH some more. It can help breaking up the bark, and specially in the case of higher pH in the basic step, a higher pH is essential for solvents such as naphtha because it makes dmt more soluble in it. If one is using a more polar solvent like aromatics and so on, then a ph of 11 or so is indeed enough in this sense, but still, a higher pH can also break emulsions and break up the bark in case of STBs.

I know in theory a very 'modest' pH range like that should work and diminish impurities pulled but AFAIK there has been no side-by-side tests done with dmt extraction and different pH to really prove that those kind of pH ranges will diminish impurities without really hurting yield. Please do correct me if im wrong and someone did test this properly.

I was mostly wondering if there was any reason not to go much under pH 4.

Thank you for your reply's.

I have not heard of this. Bu Swim told me that she is very much interested in experimenting with this narrow pH band idea and will try it during her next extraction.

To minimize possible negative effect of insufficient cell disruption it is planned to freeze-thaw finely powdered pre-soaked mhrb several times, possibly heating it quickly once or twice in a microwave in between. Swim already tested all these cell disruption teks and has found that they substantially speed up the extraction.

Methanol extraction in an extractor will follow and only then swim will proceed with the narrow pH band A/B extraction.

Swim came to this idea because alcohol extractions are extremely non-selective and it takes at least 2 A/B cycles to get clean spice after them.

Standard (wide pH band) extraction has already been done. So a comparison is possible. There is a problem of suspiciously high yield (1.8%). It looks like spice, it smells like spice, it feels like spice, but who knows...

Swim is planning to make a simple home-made m.p. tester to assess the spice purity.

More unwanted stuff will be extracted. At the same time if all plant cells are broken there will be no yield increase.

what?
sure there would.
otherwise there would be no point to taking the pH so high with STB.
the downside is picking up more unwanted alkaloids and cellular proteins

I thought we are talking about an A/B.

I would really like to know why we should raise the pH so high but this would be offtopic.

Wiki says that we raise the pH so hi, because:

"An excess of hydroxide is used in order to physically break down the bark and allow the DMT to be exposed to nonpolar solvent."

I suggested that if plant cells walls are already broken then increasing the pH would not produce higher yield. Am I missing something?

nope, must've misread what you wrote; thought you said there's no point in lysing all cells.

homogenization would allow for more mild basification in STB.
for A/B, pH of 5 for acidic phase, 11 for basic phase

Not sure if the microwave will have any beneficial effect.

Yeah the suspiciously high yields can mostly be attributed to impure spice. The m.p. tester is a great idea if its simple and works well could you please post details of your contraption on here? I think a fair few people would be interested in making one

What's an m.p. tester?

^^ melting point tester