From the HBD Archive
From: Darryl Richman <darryl@ism780c.isc.com>
Subject: re: What is your extract efficiency?
Date: 1989-02-14 15:40:18 GMT

In the Feb 13 digest, lbr@gatech.edu wrote:
"I wish Noonan had given me some idea about what compromising certain
"things would do to the result. My biggest compromise right now is
"fermentation temperature: I trust to luck. But look at what he
"suggests: gradually lower the temperature, then raise
"it briefly to get the yeast to absorb diacitals (sp?), then lower it.
"The lager at very low temperature. Then slighly higher after bottling.

Well, he is brewing at the peak. Think about how to obtain good results
with less control. In this case, just pick a warmer temperature to do
your whole fermentation at so that the diacetyls are reduced. If it's
a good compromise, you won't notice them or the esters.

"Some of his recommendations seem like labor for no benefit. I've never
"had a defective hot or cold break. I can't imagine withdrawing boiling
"wort and force cooling it to 50 degF to check for the break. He doesn't
"say that you might want to do this; he says you should do this. This
"implies that failure to do this (or, say the iodine test) may ruin
"the beer. Nonsense.

Actually, I've been tempted (but too busy) to try this. However, you
are right, it does always seem to work out in the end. But it would be
interesting to note which brews produce a stronger break. If I knew
why, I might understand how I could shorten some of the steps.

"He also says you should dough in at 60 degF and then boost to 120. I
"toss the grain into 135 degF water, which gives me 120. His method
"seems like extra work. (Will it give a higher extract? If that's
"*all* it will do the hell with it.)

More extract, and potentially reduce starch haze if you make a mistake
and overshoot your mash off or sparge water temperature later.

"Do you then use the idoine test data to determine how much longer (past
"100% conversion) to leave the mash to get the proper dextrin/maltose
"balance? Or do you merely use the test to estimate how long until
"the test will be negative? I get a negative reaction in 1-20 minutes,
"but leave the mash 30-60 minutes total. Knowing after 5 minutes that the
"test will be negative after 15 rather than 20 minutes seems of no real value;
"knowing how long to leave the mash to get the balance by some means
"other than the traditional one (wait until you measure the final gravity)
"would be useful.

Yes, it would be useful. My habit is to let the mash rest for 10-15
minutes past the starch end point (as indicated by the iodine test).
Depending on the mash temperature profile, the end point can come
at radically different times. So I do find the iodine test helpful.
But for a mash that rests at 155-158F, I can count on conversion
in less than 20 minutes (and often less than 10). The extra minutes
are becuase "end point" is a judgement call since there is always
some bit of celullose from the husks that will cause the iodine to
react eventually... I'm not really sure how long I should go, but
my beers turn out clear and stable so this seems good enough.

"" [I said I get 65-70% extract.]
"
"Darryl Richman <darryl@ism780c.isc.com> wrote:
"> You are looking at Noonan's decoction number, for infusion he quotes
"> 70%. (Are you doing decoction?)
"
"Yes. I haven't noted a great deal of difference in extract between infusion
"mashing British pale malt and decoction mashing N. American malt. The latter
"makes far more trub. I've not tried decoction vs. infusion for the same
"malt. Infusion mashing lager malt is a poor idea, isn't it?

Not in my experience. The numbers I'm quoting you are for a step infusion
mash. I don't have the facilities to decoct (is that right?). Although
I do feel that I get some of the same benefits since my mash occurs in a
tall cylinder that is directly fired on the bottom. So the thickest part
of the mash is heated and used to transfer heat to the thinner part of
the mash. I don't believe it actually reaches boiling down there, but it
must certainly be hotter than the rest of the mash...

"> Anyway, to get back to the original issue, getting 1.030 sg/lb./gal.
"> seems to be above average in homebrewing circles and is nothing to
"> be worried about.
"
"Fine. It's fermentation temperatures that are bugging me now that I'm
"trying to make lager beer. I've made satisfactory ales in the easily
"attained range of high 50's to middle 70s. I'll probably spring
"for a used fridge if I can't be assured that *one* will get me through
"the summer months when light lagers (a la Carlsberg) are so nice.

Try to compromise. If you can't find a good compromise for your yeast,
then you'll have to bite the bullet. I'm using a strain that has been
floating around the Falcons for a number of years that they claim is from
A-B and it ferments very nicely at 52F. At that temperature there aren't
any diacetyls left and the esters are unnoticed (at least in judgings).

Anyway, I'm not worried about the need for a fridge. My first lagering
fridge cost me $10. I spent the other $90 I had expected to spend on
kegging equipment. Then I happened on a chest freezer for free. I
spent the money I had saved on a deli case thermostat and so I have a
tap fridge and a fermenting chamber. So relax... this is still more
art than science. When you figure something out and turn a little
piece from art into science, that is a great triumph.

--Darryl Richman
(The Falcon's Nest homebrewer's BBS sysop 818 349 5891)

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