by bt1 » Sun Nov 04, 2012 7:05 am
Hello jim,
Just a couple pts.
Citric is not required in a TPW. Tomato paste by itself is around a pH of 4.2 and is well below optimal yeast pH. Yeasts especially generalised yeasts need to be in the 5.0 to 5.5 range. A portion of paste in a normally sized wash would bring your pH range in line with yeasts happy range.
Citric gets added to TPW as a recipe hangover from other wash types recipes notably DWWG( where wash is essentially near neutal) etc and ppl not testing pH of wash starts.
Conversely, citiric can be used in inverting plain table sugars to a single sugar type( fairly close anyway) which assists yeast speed, wash ferment times etc. Kinda like yeast on Dextrose vs. a multi sugar which table sugar is, frucrtose and glucose and other shite.
There are some arguements around that state inverting sugars adds little value. This is true for a TPW imho as there no gain to be had in a "super clean" ferment that a single sugar offers. If you where persuing a fine beer wash especially longer brewed cold temp largers using bottom fermenting yeasts or imho a fine AG whisky there is some value in inverting.
SBB hit the nail on the head with Epsom salts. If used by yeasts when they divide in cell wall regen and cell wall growth...it's not truly a yeast "food" but some magnesium compounds are consumed.
Here lies another one that still intrigues me no end...For rum washes using molasses there's enough natural mag compounds in it naturally(drived from cane itself, but notable lower in sugar beets) and i've yet to find a good reason to add it.
Bugga used my 2 pts up!
bt1