I'm working on a novel where the main character is trying his first DMT extraction. Here's an excerpt (which is purely fictional):

Last night I started my first STB extraction. I started small with 20g MHRB added to a solution of 20g lye and 300mL water. After one hour sitting in warm water (with periodic agitation), 20mL of naptha was added. After another hour sitting in warm water (with periodic agitation), I attempted to pull the naptha layer.

My first snag was that the naptha layer was very narrow and hard to cleanly pull. I got about 6mL out cleanly. I then added 20mL additional naptha, let it sit overnight. In the morning, I again pulled about 6mL cleanly.

Feeling the small amounts I was dealing with were making it hard to pull naptha, I tried to upsize things up a bit by adding about 50 mL additional water and 5g lye to the sludge (no significant reaction was noted). I transferred everything to a new container, agitated, then added another 20mL naptha, put a cork on the bottle, and went to work.

I do not plan on getting home for about 12 hours. Will the sludge mixture be okay in a glass bottle with a tight cork? I have started wondering if there might be any pressure build up issue. If so, I need to know fast to arrange to deal with it. Unfortunately, I could not quickly find an answer as to when pressure build up is an issue with STB extractions, and I am too inexperienced to know if glass bottles with corks are strong enough to withstand any pressure issues that might arise.

pressure would only build up if there was any heat source (or if you had just added the lye to water which would create heat), or if you had for example added a base to an acid (like vinegar + sodium bicarb, if you do that and close a bottle its a sure boom).

so in your case I would say youre fine

btw, tip: pre-transfer all the naphtha pull crudely to a thin tall container (no prob if a bit of black stuff comes across), and then transfer again carefully to the final container. The last bit you cant separate well just add back to the main container for next pull

Thanks.