# Lager Fermentation



## dc59 (22/1/08)

Hello everyone, I started fermenting a lager 30 hrs ago with saflager S-23 yeast, I just got a fridge for it and through the night it dropped to a temperature somewhere below 10c (the lower limit on my thermometer) no signs of fermentation have started yet. I've increased temperature up to 15c to try and get it started but nothing so far. 

Does anyone know if it is possible to kill off the yeast by having a fridge set too cold? Should I just get some more yeast or is there a chance fermentation is just lagging because of temp?

Thanks for any help you can give.


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## 0M39A (22/1/08)

iirc s-23 ferments at temps right down to 8C, so you should be fine with it.

also keep in mind that after fermentation is finished, you will need to lager it at temps as close to 0C as possible. then after this you can bottle it, so obviously the yeast can survive this, so there is no way you have killed it.

lager yeasts take a very long time to take off normally. did you make a starter for it or just pitch one packet or two packets or what?


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## chovain (22/1/08)

It's unlikely that you've killed the yeast. Yeast goes dormant at low temperatures, but the cold won't kill it unless you freeze it. I usually try pitching at the upper end of the temperature range (or even just above), and then bring the temperature down once I see signs of action.

Keep in mind your fermenter lid might be leaking, so it _might_ actually be going.


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## SJW (22/1/08)

I pitched some S-189 last night at 6pm at 20 deg C. After hitting with the air for 2 hours I let the temp come down to 12 degC over night and I went home at lunch time today and the airlock was going every couple of seconds so I dropped the fridgemate down to 8 deg C. If you airated well enough you will be fine.
With dry yeast I like to pitch around the 20 deg C mark and chill down to fermentation temps in the next 12 hours while the yeast is building up, prior to going off.

Steve


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## dc59 (22/1/08)

I just pitched one of the packets in. I'll take another hydrometer reading tomorrow and see if it has started dropping.

The packet had 11.5g of yeast in it, will two packets be better than one, or will any additional yeast make no difference to taste or fermenting time?

Thanks for reply guys, I feel much better because I no it didn't freeze.


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## SJW (22/1/08)

The one pack will be fine, but like was previously mentioned you should leave a little warmer until there is active signs of fermentation when using dry yeast. Liquid yeast is different; you should pitch that at fermentation temps or cooler.
Just let warm up a bit then chill when it kicks off.

Steve


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## Screwtop (22/1/08)

A lot of opinions expressed here Dravid. 

From Palmers "How To Brew" Here


> Because of the cooler temperatures, the yeast is less active at first. The best way to ensure a strong, healthy lager fermentation is to pitch a much larger yeast starter than you would for an ale. Where you would pitch a one quart starter solution of liquid yeast for an ale, you would use a 2 or 3 quart starter for a lager. This is the equivalent of about 1/2 to 3/4 cup of yeast slurry. In addition, the pitching temperature should be the same as the fermentation temperature to prevent thermally shocking the yeast. In other words, you will need to chill the wort down to 45 - 55 F before pitching the yeast. The yeast starter should also have been brought down to this temperature range while it was fermenting. A good way to do this is to pitch the yeast packet into a pint of wort at 60 F, let that ferment for a day, cool it 5 degrees to 55F and add another pint of aerated, cool wort. Let this also ferment for a day, and cool and pitch a third and even fourth time until you have built up 2 quarts or more of yeast starter that is comfortable at 45 -55 F. I recommend that you pour off the excess liquid and only pitch the slurry to avoid some off-flavors from that much starter beer.
> 
> Some brewers pitch their yeast when the wort is warmer and slowly lower the temperature of the whole fermenter gradually over the course of several days until they have reached the optimum temperature for their yeast strain. This method works, and works well, but tends to produce more diacetyl (a buttery-flavored ketone) than the previous method. As the temperature drops the yeast become less active and are less inclined to consume the diacetyl that they initially produced. The result is a buttery/butterscotch flavor in the lager, which is totally out of style. Some amount of diacetyl is considered good in other styles such as dark ales and stouts, but is considered a flaw in lagers. To remove any diacetyl that may be present after primary fermentation, a diacetyl rest may be used. This rest at the end of primary fermentation consists of raising the temperature of the beer to 55-60 F for 24 - 48 hours before cooling it down for the lagering period. This makes the yeast more active and allows them to eat up the diacetyl before downshifting into lagering mode. Some yeast strains produce less diacetyl than others; a diacetyl rest is needed only if the pitching or fermentation conditions warrant it.



My Opinion: For Lagers - Always pitch 2 packs, rehydrate first in ten times the weight in cooled boiled water. 22g of yeast poured on top of 220ml of water in a jug, don't stir, cover and leave for 15 minutes, then stir briskly to mix and lightly aerate, cover again and wait 20 min then pitch at the lower end of the recommended fermentation range (say 8), raise the temp over the first three days of fermentation to the upper end of the fermentation range (say 12). Leave on the yeast for 3 weeks then rack to keg and drop to lagering temp for 4 weeks otherwise rack to a clean fermenter and drop to lagering temp for 4 weeks before bottling.


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## WillM (22/1/08)

As long as everything is nice and sterile (i.e. proper sanitation) don't worry, just leave it be.

There are 2 schools of thought for the next brew.
1. Pitch at 16C, then cool to 10-12C once you get some action.
2. Make a starter or use double quantity when pitching into a 10-12C wort.


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## dc59 (22/1/08)

Just letting you guys know that the fermentation has started, its much slower than the ales I've brewed (I wasn't going to do a lager till I got a fridge), but I guess that should be expected considering fermenting temps.

Thanks for all your helpful suggestions, I think I'll rehydrate the yeast next time.


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## kabooby (22/1/08)

Hi Dravid

As others have said its normally a good idea to make a starter or use 2 packets for a lager. 

If you want to do another lager you can pour it onto the yeast cake of your current brew. This way there is plenty of yeast waiting for some wort to feed on.

If you want to meet up with a few other local brewers keep an eye on this thread

Happy brewing

Kabooby


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## SJW (22/1/08)

As he is using S-23 this is from the Fermentis site:
http://www.fermentis.com/FO/EN/pdf/SaflagerS-23.pdf.
There is lots of opinions here Dravid and if u ask five questions you will get 10 answers.
When using dry yeast I just like to see action early. By pitching, even 2 packs, at 8 or 10 deg C it takes a long time to fire up.
I guess Dravid that u need to take all advice on board , as it's all good advice, and do what works best for you. I have made award winning Lagers by using the pitching and fermentaion instructions from the manufacuter. I do agree (not that my opinion matters) with JP that if your going to pitch at 20 deg C you need to time it just right and start lowering the temp straight away. I have found that if it gets going for too long at those warmer temp it like a run away train and it will turn out a reck.
Good luck.

Steve


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## reg (23/1/08)

Hi there,

Can you please explain more about this statement

"If you want to do another lager you can pour it onto the yeast cake of your current brew. This way there is plenty of yeast waiting for some wort to feed on."
Does this mean that once you rack into a secondary you dont get rid of the yeast cake at the bottom of the fermentor, you just make another batch and mix it all together add the water and bingo??

If this is the case then do you need to use more yeast or is there sufficient yeast in the trub?
If I have to pitch yeast ten is it important to use the same one?

Sorry about the questions..Just trying to clarify for my own brewing

Reg


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## SJW (23/1/08)

Thats about it REG. I don't do this very often as when I tranfer from my kettle (AG) I transfer a lot of trub and I prefer just to pitch fresh yeast. The theory is you need to do the lighter/smaller beer first and then pitch the bigger OG beer on top of the same style. Like doing an Oktoberfest or Pilsner first then pitching a Bock or Doppelbock on top. Just remember the second beer should be darker too, so dont pitch a big light coloured beer onto a stout yeast cake. 
I would not get too hung up on this as there are lots of other ways to kick a big OG beer off if your not keen to do it this way.

Steve


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## reg (23/1/08)

So if I like to brew lagers and Pilsners then I would use the same yeast cake how many times before it becomes risky, or can I keep using it till I decide to brew a dark ale?

And sorry to ask again but do I have to keep re adding yeast to every new brew done on an older yeast cake??

Can you treat the trub like a yeast starter and put some in a bottle in the fridge and restart when needed??

Confused

Reg


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## SJW (23/1/08)

There is a thousand threads here on Yeast washing and the like. If you are not going to pitch a bigger beer on top just scoop some slurry up in a sanatised cup and pitch that.
Do a seach on Yeast washing.
Its only worth doing if your using liquid yeast due to the higher cost. I would not bother with dry. As I said I don't like doing this unless I am pitching a big Doppelbock onto the yeastcake, with any other brew I would either step up a liquid starter or pitch 2 packs of dry. I just dont like to risk the transfer of an infection to the second brew or the transfer of any residule hop/trub/beer flavours to the second brew.
But its up to you.

ps. A lot of blokes do this all the time and can keep a yeast going for 6 or 7 brews with great results. Maybe they can coment.

Steve


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## Hutch (23/1/08)

reg said:


> So if I like to brew lagers and Pilsners then I would use the same yeast cake how many times before it becomes risky, or can I keep using it till I decide to brew a dark ale?
> 
> And sorry to ask again but do I have to keep re adding yeast to every new brew done on an older yeast cake??
> 
> ...



Hey reg,

You're on the right track. When you pitch onto the yeast cake, you don't need to add further yeast.
Also, do a search for "yeast farming", to learn how to re-use the slurry at the bottom of the fermenter.
You can store this away in the fridge for several months, and use it again in another brew without needing to 
use a new yeast packet.


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## reg (23/1/08)

I am doing a search now and came across some great info..

Maybe if I looked before asking I wouldnt have hijacked the thread.

Cheers
Reg


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## tangent (24/1/08)

I just did a pils with 3x packets of dry lager yeast. Took off like a rocket and is down to 1.011 and still chugging away. Fridge is set to 9C the side of the fermenter is reading 11C


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