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Goat

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Is a fast ferment a problem with flavours etc?

I did a brew on Saturday with a SG in the fermenter of 1.052. pitched onto the yeast cake from a previous lowish gravity brew (1.037). after an hour or so it was off and running and boy did it go!, I had to have a tray under my blow off tube in bucket - that sucker went off. Anyway - I took a reading yesterday and the gravity was 1.010 or thereabouts. Thats 42 gravity points in 48hours. Now I'm worried if they is a penalty for this feverish activity...

The yeast is wyeast 2308 in a pils recipe of 5.5kg Hoepf Pils, 1kg Hoepf Vienna and .15kg Hoepf Melanoidin. put some wyeat nutrient in there too (just for good measure...)

If I use 77% attenuation I should should get to 1.011 - so its done. If the graviity has stayed about teh same I will pull it out of the freezer for a diacetyl rest and secondary / keg on the weekend.
 

Justin

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In my experience the general rule is no. BUT, the more vigourous the ferment the more heat is generated and if your brewing a lager a rapid speed can be a problem due to endogenous (internal) heat generation.

When you pitch on a cake (I usually at least halve my cake) you can expect a rapid ferment. I've been doing this lately for a number of ales and regularly see them done in 3 days. It's great, and they are still to my knowledge fermenting within my specified temp range. And to boot I get some fantastic clean flavours and beautiful beers out of them.

However, in a lager what you may have seen is a rapid ferment due to not only a large yeast count but also a higher than desired fermentation temp due to pitching at too high a temp. What temp did you chill your wort to before you pitched? Anything above your desired fermenting temp when pitched, with a lot of yeast is going to be tough to get back down IMHO before the damage is done. When you pitch a yeast cake of lager yeast at say 18C it goes off like a rocket and you can probably expect the gravity to drop by half in a couple of days before the temp gets down.

Hope it helps. My advice when pitching a yeast cake into a lager, make sure you pitch at fermentation temp.

Cheers, now lager that sucker ;)

JD
 

Goat

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Thanks Justin - interesting stuff.

I chilled the wort to about 22 which was the best I could do with tap water (forgot to chill some) then let it sit/aerate for about 3hrs to cool further so I would say it was below 20 but certainly not 18 so there might be a bit of an issue there (certainly explains the rapid start)

I put it pretty much straight into the freezer and set it to 15deg then stepped it down to 11 the next evening.

This is for the Chrissy pack, so I hope I haven't stuff up another one... I'll diacetyl over the next couple of days and larger it as you suggest.
 

Guest Lurker

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Take a swig, should soon see if is crisp and dry or solventy and fruity. You've got about 4 weeks before you have to get the goods to my place so might be pushing it to do another one, I'm sure it will be better than any of the apricot tasting lagers I have made without temp control.
 

Justin

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That's the answer then. Not to worry, you might get a few fruity esters above what you would normally expect but hopefully it is still ok. You may have made a Kolsch instead ;). Do as you said, diacetyl rest then carry on lagering.

That's basically the recipe I made on Saturday as well, except for the melanoidin and I used 2206 Bav Lager. You may have read my cooling issues under the CFWC woes thread. We got to 14C for pitching but we aiming for 9-10C. We were at one stage pumping put of the fermenter through the CFWC and pump and back into the fermenter trying to get the temp down. Used 1/2 a yeast cake. In my opinion you can't beat pitching a lager on a yeast cake, they love it ;) and it beats building up a big starter.

FWIW I only chose 18C as an example of pitching at too high a temp, I still reckon you should chill further (approx. 10C, even 8C IMHO) in future though. Get right, right down. Your options here are to either use a pre-chiller with some ice or stick the fermenter in the freezer turner right down before you pitch your yeast. Some people recommend pitching a little warmer to get the yeast count up quickly before then chilling it down. I don't really agree with this practice, pitch enough yeast and you don't have to worry about this practice.

I have on occasion just done a light beer like a Munich helles just to get a lager yeast cake for the next beer. At least then you can drink the starter ;)

Cheers, Justin

I'm sure it will still turn out ok.
 

action man

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a fast fermentation especially with lager yeasts can result in high levels of esters. so instead of that crisp clean lager flavour you may end up with more of an ale style beer. its not that much of a problem, as it has happened to some of my beers and they are still fine, just give them a longer lagering and diacetyl rest and they will get better.
 

Goat

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Thanks Justin and GL - I hope this sucker is OK 'cos its my second go at it following the gravity cock up of last weekend...

The FAQ from Wyeast Labs tends to back your 18deg Justin :

Lager yeast can be started cooler than ale yeast if it is important to minimize ester formation at the higher propagation temperatures. Typically the yeast (the question was specifically about 2308) can be started in 75 F wort and pitched in 24 hours. Start your 2308 in 65F wort instead of 75 F. Hold for 48 hours until high kerausen, then pitch into wort.

In the past I have chilled 30-40 L of water in the freezer overnight before brew day and recirculated this through the chiller after the tap had done all it can - it really heaps dropping those difficult last 10 degrees...... next time
 

nonicman

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Just tried a sample of my first lager (a kit Morgans Blue Mountain, with LME and SafLager yeast), it's been brewing for nearly two weeks at around 10-11C (except for a two day period where I dropped the temp to 2C whilst I carbed my first keg.). It smells and tastes like apricot. Now I have a AG version in the same freezer, which with the apricot in the kit brew is worrying.

Any suggestions?
 

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