I started an extraction today, 500g rue pressure cooked for 120 minutes, filtered and then based to ~9ph. Same as I've done it numerous times. Except this time there is very little harmalas falling out, >1% I guess. I usually have results 3-5%.
This particular seed is from a different source.
Is it possible that sometimes rue has low alkaloid content?
Probably just the seed leading to this outcome?
I've not encountered this before.

Sounds like a bummer indeed, is basing higher than 9 nothing better?
I'd poor some lye power on it

I would never have considered that.

So I decanted 2 litres of my 3 litre solution into another jar and added about "that much" lye to it. After about 24 hours I was looking at it and it appeared that there was something appearing on the bottom of the jar.

Now, a couple of days later there is about 2cm of alkaloids settled in the bottom and 5 cm of solution above it that is noticeably clearer than the rest of the solution above it. The other jar that had originally the bulk of the alkaloids after 48 hours now has a similar amount and the solution is clearing at a far slower rate.

I've never seen this before, I'm not sure what it is/I did to make the alks so fine that they would stay suspended for so long in the solution.

Possibly, as it is now winter, the temperature could effect this dramatically? Possibly because the seeds got free of the baggy and went everywhere in the cooker? Possibly because I left it cooking longer than the usual 90 minutes up to 120 minutes? Maybe even a combination of these things? The acidity of the cooking solution is different too.

It's hard to tell what's going on as there's so many variables.

Curious about final yield.
And yes, settling time rules.

This could be of interest:
Preparing syrian rue extract, does your base matters?

Cook it at least twice, pH below 5.
Base it to at least pH 12.

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

Interesting thread, thanks Jees.

I've never based further than sodium carbonate will take me, I didn't realise there was more to be had by going higher. I'll have to to give it a go starting with lye. I haven't really looked at this section of the forum in the last few years. It's great to see new and excellent information being added.

I've tested pressure cooking twice, twice, at 15PSI for 90 minutes in acidified water. The second cook yielded >5% weight of the first cook from the same seeds both times.

It's looking pretty curious now with a thick high band of suspended alkaloids in the jar.