I am looking into filter aids capable of dealing with the worst sludge coming from MHRB or P. harmala.

I usually reduce MHRB or harmala tea to manageable amount, then let it sit overnight to allow fine insoluble impurities settle.

Then I decant the supernatant liquid and filter the rest.

My current weapons for fighting the slught include:

- repeated addition of hot water, sedimentation and decanting
- glass wool, funnel + vacuum filtration
- Celite (diatomaceous earth)

When filtering harmala sludge, the only thing that currently works for me is making a pad of Celite inside Buchner funnel, then adding mixing few spoons of Celite into the watery sludge, then filtering it with vacuum on. This procedure is however still quite lenghty.

I was thinking about these aids:

- sand
- aluminium sulfate (coagulant)

The sand provides coarser filter that Celite, hence might improve filtration speed.

As for the aluminium sulfate, it is often use as water purification aids in swimming pools, because it easily adheres to impurities, then falling to the bottom. It should not be filtered though.

I am afraid however, the aluminium sulfate will grab harmaloids with the impurities (in re-acidified sludge).

I might give it a shot though, but currently the easiest method seems to be just top up the sludge-containing beaker with hot water, mix it a bit, then decant the liquid.

This way most alkaloids get extracted without the tedious filtration.

What do you think and what you use?

With rue seeds I don't have any problems. I don't grind the seeds, so this may be the reason.

After boiling them, I don't reduce the liquid, I just add lye to the unreduced tea (you don't need much lye anyway, whether it's a liter or 20), let it settle overnight, decant off the bulk of the supernatant and run the precipitate through coffee filters, which is fairly quick.

My yields are 7.5% pre-manske and 6.5% post-manske.

As for MHRB, I don't have as much experience cooking it, but the insolubles seem to settle enough to make the acidic liquid clear, at least at concentrations where 1 g dry plant material corresponds to 2 ml of liquid. Maybe it just takes longer?

I second that method, although even with whole seeds there still seems to be some solids that will settle in the solution if left in the fridge overnight. I've also done a course grind and filtered through high thread count cotton fabric then settled overnight in a fridge, with both of these methods, that day in the fridge seems to be the magic.

Adding lye straight away makes sense. I will try it instead of reducing the liquid (I am reducing something like 20 L to 5 L so it takes several hours on gas stove).

I don't grind the seeds and filtration is not a problem unless I dissolve the crude harmala alkaloids in a minium amount of hot vinegar. There are lot of gunk-like trapped impurities. This blocks every filter so what I do is mixing the gunky sediment with lots of Celite, then filter everything with the aid of vacuum. The filtration is very slow but it works and eventually there is a brown cake on the filter and perfecly clear filtrate.

Note that even when the vinegar solution looks clear, adding salt (Manske) pushes more of the brown precipitate from the solution. This gunky material is a real pain in the a** to filter. Fortunately, there is negligible amount if the liquid was already filtered.