Hello.

Swim has done lots of extractions in the past, but hasn't done some for a while..
Ended up with using the q21 fluffy white tek with fantastic results..
Always came out with large yields and great white Chrystals.

He now found a new bark supplier for Brazilian MHRB, which had some very good reviews on the quality of the bark.
Now SWIM was doing a q21 extraction again, which came out with a very low yield.
he was using the same ingredients as he did earlier, (CaOH, vinegar, tapwater, ..)

he was doing 2 extractions with each 100gr MHRB, 100ml vinegar, 100ml tapwater, 75gr CaOH)
first one came out as a crumbly-cake-consistency as he was used to it..

heated in a crockpot for a while,
100ml warm Naphtha, which was reduced before freeze-precipating to around 35-40ml
1. Pull: ended up next morning with not even 100mg of white Chrystals in the dish.
2. Pull: little yellowish, but he yielded even less..
3. Pull: yielded another 60 mg of white spice.

results in around 200mg spice from 100 gr MHRB....

So he decided to change the consistency a bit and made the 2nd batch a little more soup-like.
added more water, vinegar and lime.
But after 1st Pull, he resulted in same low yield..

In both batches the Naphtha was not even becoming cloudy after reducing.

I know, the quality of bark varies a bit, but in all those years, he never ended up in such a low yield.
Anyone heard of such a crappy MHRB before?

SWIM is pretty sure he has done everything correct.

He now thinks of rather giving lye a try instead of the CaOH. (Maybe the CaOH didn't base enough)?


Would it work to add water and lye to the mix, so he could do another pull and see how that turns out.??

He couldn't believe he was sent such crappy bark...:-(
even with some low-yielding Mexican bark he had far better results earlier..

any idea on this?

I would suggest that adding more vinegar was a waste of materials at this point. For it to have any effect, you'd have to neutralise all the lime that was remaining from the first round, and then some. Then with re-basing you'd have to neutralise the excess vinegar again with a sufficient excess of lime.

On the basis of this observation, could you outline what you did from the very start of your process? Because your action might indicate a lack of understanding of some aspects of the extraction process. This would help to clear up the question of whether your bark was in fact of low quality from the outset.


If you have an excess of calcium hydroxide in the mixture it is possible to add sodium carbonate, which will react with the lime to produce calcium carbonate (chalk) and sodium hydroxide. So, there's no special need to add lye if you have washing soda available.

When using lime, patience can be an asset. Letting the mixture sit for a day or two can often be advantageous. Use a tightly-sealed container to minimise absorption of carbon dioxide from the air. Incidentally, powdered lime stored in contact with the atmosphere will slowly absorb CO2, reducing its efficacy over time. Make sure your container is air-tight or even do as lime renderers would and store your lime as a paste ready-mixed with water.