I think that was me. I'm not sure acorns would be a suitable substitute for galls. They are not the same.
Originally Posted by htmlguru4242
Galls are irregular plant growths which are stimulated by the reaction between plant hormones and powerful growth regulating chemicals produced by some insects or mites. Galls may occur on leaves, bark, flowers, buds, acorns, or roots. Leaf and twig galls are most noticeable. The inhabitant gains its nutrients from the inner gall tissue. From: http://www.uky.edu/Ag/Entomology/ent...rees/ef408.htm
My understanding is that any plant material will release tannins as the material decomposes, but there are some things, like the galls, that are higher in tannins and that's why those sources were preferable.
As to the definition of inexpensive, I go by the motto, "Time is Money". If it takes me a lot of time to accomplish something that I could have just gone out and bought, then I see that as a possible bad use of my time. And the money it took to use that time...
But I too remember those days in college, like when we tried to make rocket engines from a couple pounds of ammonium nitrate fertilizer and suger, or the time we made SCUBA diving weights from a gallon bucket full of wheel-balancing weights. (I actually still use the diving weights for things like keeping the Xmas tree from falling over, or light stands. I think I've almost recovered the time expense from that project after 20 years.)