200g batches with the STB teks have been coming out great. 1:1:15 ratio and a freeze precip nets about 2% yield. An A/B was tried to reduce the need for re-x but so far there haven't been any x-tals forming in the freeze

The process: boiled 200g mhrb powder in about 2 quarts of water for approximately 2 hours then decanted 1/2 the water and refilled. This was repeated 2 more times leaving 3 quarts of juice and powder goo which was discarded. The juice was reduced to less than 5ph during the boils using white vinegar. The solids from the jars were decanted and the juice consolidated into one gallon jug.

From there the usual naptha extraction was performed and freeze preciped. 3x 90ml pulls with naptha were done and when no crystals formed after 2 days, the volume was reduced by evaporation by about 1/3. When no crystals formed from that a second reduction was done by 1/3 and a very small amount of crystals barely started to form, nothing like the usual precips from STB, possibly 10 mg. An additional pull with only 30 ml yeilded the same results, and that was after shaking through multiple times.

It seems like an issue with the boiling, as in the spice never made it to the juice. any suggestions for that? I could boil longer I suppose, but would that help? I had it on medium and had to refill the water a few times to keep the level right, that shouldn't be the issue should it? I've also read about basifying to free the spice and then acidifying to keep it from being destroyed by the heat, is that worth trying?

Thanks

Did you only add vinegar for the reduction? The boils themselves should be acidulated.
How much lye was added before the naptha extraction? Insufficient basification is a primary cause for poor yields in A/B's.

Similar thing happened to me once. More lye fixed it. If that doesn't work, I suggest using an acid for the boil like Noman said.

Sorry if that was a little unclear, it seems there's always a need for more details.

The boils were done at 5 pH or less by adding white vinegar. This was checked several times throughout the process since the water was drained and added. The pH meter in question doesn't account for temperature, but that shouldn't throw it off too much right? HCL could be used next time if necessary, what is the appropriate pH range?

The pH of the basified juice was at about 13.5 before the last pull and the color obviously changed to a murky black. That was usually enough for the STB teks, but it wouldn't hurt to bump it up a bit before scraping the whole thing. The meter only goes up to 14 tho...

Other possibilities: meter is WAY out of calibration or the boils were not done long enough. No pressure cooker currently available and it's a pain to keep adding water as it boils off, but maybe the boil needs to be 3 hrs each? Try a recalibration of the pH meter and test again? Whatcha think?

Thanks for the quick replies folks!

Ah that changes a lot! Now its just odd . From my limited experience with A/Bs, I've noticed just a small amount of vinegar was needed and my boils were 3x30 min, then letting them stand in the hot water to cool down and decant, then reduce the total liquid.

Is it the same batch of MHRB used from your previous STB's? If not, could be some bunk bark. It looks like you had good results with the STB's so you probably left the naptha in long enough and have a cold enough freezer, etc. Hopefully someone will jump in with a better contribution. Good luck!

Isn't it tho? Same batch and the freeze precip was done exactly the same... At this point I'm thinking it's either not basic enough (even tho the color is right and the meter reads 13.5) or the spice did not make it out of the mhrb powder.