I used to use current-limiting diodes but went back to current limitation by a series resistance, using a rheostat. (Incidentally, the word rheostat means "static flow maker.") Preventing run-away seems more important than uniformity.
I can set the rheostat to achieve the upper limit of current desired. This is usually determined by the range of the micro-ammeter I use, a 0-500 microampere analog meter, and the spacing of coin electrodes, about 3 inches, and a constant-voltage power supply (30VDC) taken from a discarded Mac computer. The brew time is loooong, but this is not inherently a bad thing. The stirring is thermal, mainly because it is so handy and rugged. Best regards, Matthew
