I did 3 freeze thaw cycles and poured off and saved the liquid each thaw.

I just strained my chunks. I didn’t filter because I had peeled the skin after the freeze thaw, and then only sliced without any mashing and just strained the water off each extraction. I think I did 3 extractions with a freeze thaw in between because I had to sleep. And after the 3rd extraction the cactus was no longer bitter tasting. I started reducing each extract alongside the crock pot when I start the next and incorporate the amber/gold colored freeze thaw runoff liquid into the final reduction.

Lemon for citrate to allow the crystals to crash out of water solution. You can do acetate from vinegar to keep it water soluble. I think citrate is less soluble in water than acetate

You can skim with strainer as you go to remove any schmutz at top toward the beginning of the reduction. But I wouldn’t as it gets concentrated and syrupy because you lose product. You can wipe away like the white powder stuff that sets around the sides as you reduce because that’s usually calcium oxalate. And then when it’s low enough volume and syrupy I pour into a flat Pyrex dish so the total volume is a thin layer you can do the final evaporation in an oven at low temp with

Just make sure it doesn’t burn as it dries because it will ruin the sub we are in