My question(s) is/are regarding plant extracts for use topically.
First of all, if you make a plant extract with alcohol, and then then the alcohol evaporates out, is it still an extract? Would it then be perishable? (i.e., need refrigeration.)
When they use plant extracts in cremes, lotions, conditioners etc., what kind of extracts are typically used – water-based, alcohol-based, or what? How do they stabilize it; or is the amount just so small that it doesn’t matter?
I am asking because I have made a plant extract for use on my skin, and I can smell that the alcohol is evaporating out. That would be good, since alcohol is drying, but I don’t want it to rot. If it makes any difference, it’s from a very dry type leaf, the kind that goes through my juicer and nothing comes out. Hence the alcohol.
Generally, an alcoholic extract is called a tincture. I’ve never seen anyone extract a plant and dry it to completion, but when that’s done, it’s called a dry extract. If there’s no residual water, it’s not going to rot. However, if you want to extract the plant with alcohol and yet avoid the dry skin and the evaporation, you can make a fluid extract (i.e., to the tincture, add water). Try to add a little water at a time so the alcohol solutes don’t flop out of solution.
When they add plant extracts to cosmetic products, there’s usually not enough to matter, and the medium is whatever is best for the plant. There’s one company that specializes in such extracts for the cosmetics industry that mostly uses propylene glycol and water, and those can often be used in quite large amounts without breaking down the product.
Thank you, Nametag. I realize that I wasn’t clear about my tincture – I used rum, because that’s what we had around, and a little water too. So what I have is a fluid extract, as you described. Should I be refrigerating it?
If what is dissolved in the alcohol does go out of solution… er, where would it go? Into solid particles at the bottom?
Most solids will precipitate like that; other solids will just get gummy. As long as the particles are fine enough that they can stay suspended after a good shake, it’s not a big deal.
The Wikipedia article on herbalism is pretty good, and has references.