I just read two contradictory things regarding caffeine/coffee and sclerotia development.
The first is from Hippie3 who says here in 2004 that he "read that caffeine has been correlated with a boost in sclerotia formation with mexicana". This would explain the coffee soaks in some mexicana teks.
However, in a response to Mycotopia post Caffeine, Tannins, and Polyphenols from Coffee Residues Bad for Mushroom Growing user Invitro cites a scientific article entitled Increase in Endogenous and Exogenous Cyclic AMP Levels Inhibits Sclerotial Development in Sclerotinia sclerotiorum (pdf) saying "Caffeine, IBMX, and NaF all block sclerotial development and are expected to increase cAMP levels. Elevated cAMP levels appear to block early sclerotial development since sclerotial initials are not observed or are greatly reduced in number in cultures amended with cAMP. Developing cultures transferred to cAMP-containing medium before sclerotial initiation did not produce sclerotia, whereas cultures transferred after sclerotial initiation continued to develop mature sclerotia. Although cAMP regulates sclerotial development, the nature of this regulation remains uncertain. cAMP regulation may be indirect in that signaling through a cAMP-dependent pathway may stimulate filamentous growth, resulting in hyphae which fail to differentiate into sclerotia." The species of mushroom here is S. sclerotiorum, but I imagine the knowledge is transferable.
I hate to say it, but citation wins over no-citation. I will not be mixing in a caffeine source.
Edited by PinkMenace, 24 July 2018 - 09:14 PM.