From the HBD Archive
Subject: propane questions & esters from low lipids
Date: 1992-06-05 20:50:26 GMT

Ive got a question about propane regulators, flow rates and freezing I am building a kettle burner that will fire my kettle/mash tun as well as
heat the sparge water. My burner supplier (Solarflo) states a maximum input
fuel rate of one gallon per hour. This is supposedly regulated by a 10" water
column pressure regulator (the manufacturer claimed this was about .5 psi).
I have seen (and own) a backyard BBQ with a regulator rated at 11" water
column pressure. I assume these are not compatable, comments. Also of
concern is the ability of the regulator and couplings to supply 1 gal of
propane per hour without freezing up. I am trying to gather information
on regulators and flo rates so I build the optimum setup. Any info is

Re: Micahs Ester post

Its very satisfing to read some technical discussions about brewing in this
digest and I thank Micah for contributing to this. I have to question some
of the statements, though no flames. I dont see how you can brew well made
clear beer without recirculating some runoff from the lauter tun. I am
currently using slotted sheet as a false bottom and a 20 minute recirc is
mandatory for remotely clear runoff. As for oxygenation of and browning
reaction of hot wort, it doesnt affect flavor, and unless you are making
a very light lager (pils) the resulting darkening of the wort is not
significant. I follow the reasoning of particulate matter flocking to the
proteins, but why add particulate matter thereby adding hot trub and reducing
hop utilization. If you have sufficient amounts of calcium in the boil,
the proteins will flock well anyway. As for yeast autolyzing from lack
of lipids: this is irrelevant if you are maintaining healthy viable yeast
stocks. Yeast need to synthisze (sp) sterols to transition from the
resperation phase to the fermentation phase. Yeast will use stored
glycogyn reserves from the cell interior, respire oxygen and produce teh
required sterols. The important ingrediants are oxygen (which most
homebrewers can never get enough of in the wort by shaking) and glycogen
stores. Stored yeast (ie Wyeast) deplete glycogen during storage without
food and are thus in a position to display inordinant lag times. This
coupled with the low O2 in the wort leads to the poor Wyeast ferments.
Without adequate supplies of O2, the yeast can feed on the fatty acids
present in trub (from the cold break). This is how yeast synthisizes
sterols in a low O2 environment (read homebrewing). This is why it is
a poor idea to rack off the cold break prior to the end of the respiration
stage. This is also why you need a clean, glycogen rich supply of yeast
slurry at pitching time. On a related topic, anyone use an oxygen injection
system on thier chillers? I am designing one now and am looking for tips,
ideas that is.

Jim Busch


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