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Angus MacDonald

Well-Known Member
Jul 20, 2018
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Inverness, Scotland
So I'm thinking of making a lager in winter and I know that you roughly want 8 - 10C for fermenting. I was gonna stick the lager in the shed during winter to keep it at a cold enough temp but the only time I'll have that stable range during winter is... probably October to mid November. From mid November onwards, the temp will dip between 4C to -2C until mid February.

How low can the yeast go in temp for lager? Will it survive shed temps below 8C?
Lager yeast is good in the 40-50's (5C-13C ish). You really only need to keep them within range during primary fermentation, and then you can lager as cold as you want really. The yeast will just go dormant and drop clear unless you freeze it which might kill them. However, I've also read of people accidentally freezing their beers and having good results so they still survived.

Sounds like good weather to do a Maibach and have it ready in May.
I brew in the winter because the temperatures are fine for producing Lager and Pils where I live. I start the brewing season after second frost. Usually, the temperatures work out but when they don't I call the beer, Steam Beer, and then, I smash my face against the wall for five or nine minutes for screwing up Lager and Pils. Steam is OK and I used to pound down Maytag's Steam Beer but that was then. This is my schedule. Light Lager, Ale 1050, 1053 or so gravity, minimum four months aging, 1055, 1058 Pils, fine Ale usually six months, 1060, 1065 Oktoberfest, IPA, Bock, usually nine months. I don't produce RIS, Doppelbock, Wee Heavy type stuff because I'm too lazy. Besides, that stuff is real difficult to make and if I failed I don't want to smash my face into a wall any more than necessary.
If the recipe that you decide on recommends using a single infusion brewing method, high modified malt, only primary fermentation, a diacetyl rest without krausening and adding priming sugar. The beer will thin out and deteriorate before completion of the aging cycle. Sometimes, gushing and over carbonation can happen.
To make Lager and Ale a Beta rest is required. During the Beta rest mash is held around 140,145F. Conversion occurs during the rest. Conversion happens when Beta converts simple sugar, glucose into complex types of sugar, maltose and maltotriose as Alpha liquefies amylose. So, saccharification is taking place at the same time as conversion and when amylo-pectin is in solution dextrinization begins, slowly. Alpha is responsible for liquefaction, saccharification and dextrinization. Beta is responsible for conversion which has nothing to do with starch.
Now, after conversion occurs during mashing, the next stuff happens during fermentation. Yeast loves glucose way more than it loves maltose and maltotriose. So, during primary fermentation yeast rips through all of the glucose first and it lets the complex sugar alone for a little while. After primary fermentation ends the beer is transferred off the goop for second fermentation to begin. (We don't want trub goop transferred because after awhile yeast begins to love goop and off flavors associated with home made beer pop up and since we're going to age the beer for months we don't want weird flavors showing up. Actually, it's better to quickly cool the wort, rest it an hour or so overnight and rack the wort off the trub before dumping in yeast. To lessen trub skim off hot break as it forms and when it ceases to form or it greatly reduces add bittering hops. Less hops are needed because the wort will be a little cleaner).
Get this, it's pretty good science type stuff. The Great Magnet equipped yeast with an enzyme and during second fermentation, second conversion occurs because yeast begins to like complex sugar. So, what happens during second conversion is yeast absorbs maltose through the cell wall and the enzyme converts maltose back into glucose and the glucose is expelled back through the cell wall. Yeast uses the glucose for fuel and gravity reduces closer to expected FG. The same thing happens with maltotriose during the aging cycle and the beer naturally carbonates and expected FG is hit. The problem with using only a Beta rest, the beer will be thin and dry.
To counteract thinning a type of starch is used. The starch is amylopectin-pectin, it makes up the tips of the kernel. Amylo-pectin is heat resistant, complex starch and it is the richest starch in the kernel because it contains dextrin which is a type of tasteless, non-fermenting, sugar responsible for body and mouthfeel. The starch begins to enter into solution slowly at 169F and during the infusion method temperatures are not high enough to cause enough amylo-pectin to enter into solution before Alpha denatures. The starch ends up in the spent mash, paid for and not touched. When the decoction method is used mash is boiled a few times and each time the mash is boiled more and more amylo-pectin enters into the mixture. Each time the boiling mash is added back into the main mash dextrinization occurs when Alpha liquefies the starch chain releasing A and B limit dextrin, responsible for body. The finest Ale and Pils are produced from dextrin rich wort.
When you have a moment take a look at the recipes on Weyermann Malt website. Weyermann produces light and dark floor malt. The malt is slightly under modified and it is low in protein. I have used the malt for years for Lager and Pils and it is fine malt, very consistent.