Lager Yeast Pitching Temperature

[Bribie G]

Last night I pitched my Chinese Pale Pilsener with a litre of quite dense slurry of S-189 at 21 degrees. This morning it's down to a nice 15 degrees and krausening mightily. I'll ease it down to 14 and keep it going on that for about 10 days, lager for 10, keg for 10 then serve. I find that this yeast is quite forgiving at the mid-teens temperatures which is why I use it for my quick turnaround House Lagers.

However re the pitching temperatures, I know this has probably been hashed over before, but I'm a bit puzzled because I hear some people say they pitch warm then drop, and others who drop the temperature (say to 11 degrees for a yeast such as W 34/70 or Wyeast Lager yeasts etc) and then pitch big at that low temperature. Can anyone explain why pitching warm is worse than pitching cold, or vice versa?

 

[AndrewQLD]

If your pitching a large volume of yeast it will start to ferment quite quickly and aggressively raising the temp of the wort a fair bit, so while you might pitch at 15 the temp can easily get up to 18+ in the wort without you realising it.
If I pitch large I also pitch at the lower temp ranges to help negate the thermal effects of the yeast, it slows the yeast down a little and helps stabilize the temp of the wort.

Cheers
Andrew

 

[Fourstar]

Simple answer.

The inital stages of fermentation and the growth phase will determine how 'clean' your lager (or an ale for that matter) really is. Basically with ALL beers you should start cold and warm up as you go. If you go through the process of starting warm and then cooling down you can run into issues with early flocculation resulting in fermentation precursors behing left behind in hte final product.

In other words, if you want the optimum results for your lagers and are not concerned about lag time/growth period. Start COLD and ferment as cold as you can for that particular strain then slowly ramp towards the end to ensure any fermentation by products are scrubbed out where possible.

 

[Bribie G]

Thanks Guys. My XXX lager which I made fairly quickly for a party (guys sampled what was left in the keg at the hop packing day) did turn out a tad fruity but as it was a medium gold with some Crystal, and also well hopped with cluster, the slight fruit did suit the style, but I agree that for a Bo Pils or a German Lager (or a Chinese International Pilsener ) then the cleaner the better.

 

[Synthetase]

I'm a proponent of pitching warmer (within reason) and bringing the temp down. As you know, yeast multiply faster at warmer temperatures (S. cerevisiae grows best at 30 degrees celcius). Since there will be no fermentation (due to the presence of oxygen in the wort) in the initial stages post pitching, the yeast will be multiplying quickly via aerobic respiration. Once the oxygen has run out, fermentation will begin and you want that to take place at your cooler lager/ale temperatures.

In short, I want as many cells present as possible once fermentation begins and I try to skew conditions toward that.

 

[cdbrown]

My last two lagers I followed some advice from kirem.
Pitched 2 packets at 10C, after 4 days turned temp down to 9C, then following day 8C and so on until 5C. After a total of 10days it was more than 2/3 through transferred to secondary and let it finish which was another 5 days. Transferred to keg and chilled at 2-3C for a few weeks for lagering. Kirem usually transfers straight to keg instead of secondary and uses the final few days to provide some natural carbonation.

Method provides very nice clean lagers.

 

[Bribie G]

Lagering in the keg sounds like a good idea, I don't suppose the beer cares what container it's being lagered in

 

[Screwtop]

If your pitching a large volume of yeast it will start to ferment quite quickly and aggressively raising the temp of the wort a fair bit, so while you might pitch at 15 the temp can easily get up to 18+ in the wort without you realising it.
If I pitch large I also pitch at the lower temp ranges to help negate the thermal effects of the yeast, it slows the yeast down a little and helps stabilize the temp of the wort.

Cheers
Andrew

Exactly...........it depends, pitch rate/pitching temp/yeast strain/yeast health. As for 189 I like to ferment it at 12 as stressing it produces acetaldehyde (green apple) so a big pitch if pitching at 9, normal pitch if at 12.

Screwy

 

[hughyg]

My last two lagers I followed some advice from kirem.
Pitched 2 packets at 10C, after 4 days turned temp down to 9C, then following day 8C and so on until 5C. After a total of 10days it was more than 2/3 through transferred to secondary and let it finish which was another 5 days. Transferred to keg and chilled at 2-3C for a few weeks for lagering. Kirem usually transfers straight to keg instead of secondary and uses the final few days to provide some natural carbonation.

Method provides very nice clean lagers.

So is that let it finish out at 5C then in secondary for 5 days?

 

[Zwickel]

I'm a proponent of pitching warmer (within reason) and bringing the temp down. As you know, yeast multiply faster at warmer temperatures (S. cerevisiae grows best at 30 degrees celcius). Since there will be no fermentation (due to the presence of oxygen in the wort) in the initial stages post pitching, the yeast will be multiplying quickly via aerobic respiration. Once the oxygen has run out, fermentation will begin and you want that to take place at your cooler lager/ale temperatures.

In short, I want as many cells present as possible once fermentation begins and I try to skew conditions toward that.

I wouldnt recommend that.
The yeast growth should take place outside the fermenter. At higher temps the yeast produces a lot of unwanted stuff, that all would be in your beer in the end.

If one likes to produce a clean lager or pilsener beer, let the yeast grow in a separate vessel, so you can decant the most of the unwanted stuff prior pitching.
One should produce as much yeast as is needed to ferment out the whole batch and then pitch as cold as the yeast allows.
A yeast growth in the fermenter shouldnt be targeted.

Cheers :icon_cheers:

 

[gjhansford]

Lagering in the keg sounds like a good idea, I don't suppose the beer cares what container it's being lagered in

For all my pilsners and lagers I use 2 packs of Weihenstephan dry yeast from Ross (rehydrated) which I pitch at between 18C and 20C with the fermenter in the fridge and on it's way down to about 12C. Buy the time the yeast gets going the brew is at 12C and I leave it like that for 2 weeks. (Grain bill is 4.5kg Weyermann Pilsner, 0.5kg Carapils and 0.2kg Acidulated for my 'green' pils).

I transfer to a chilled keg, add 100g of dextrose for carbonation, and leave it for at least 2 months, lagering at serving temperature. Makes a clean pilsner or lager ... the punters, especially the ladies, love them. Had one keg that I 'forgot' about ... it was nearly 4 months old when cracked ... and it was the best!

I have no idea why, but I used to leave the freshly kegged beer at room temperature for a week :wacko: ... I guess I was thinking I was giving the dextrose time to do it's carbonation thingee ... and then larger it. But I get the same carbonation at the lower temperature largering and the brews are real crisp and ... well the word is ... pilsner style!

For what it's worth ...

PS: Will be trying a liquid pilsner yeast next. Expecting something even better. :icon_drool2:

 

[drsmurto]

I wouldnt recommend that.
The yeast growth should take place outside the fermenter. At higher temps the yeast produces a lot of unwanted stuff, that all would be in your beer in the end.

If one likes to produce a clean lager or pilsener beer, let the yeast grow in a separate vessel, so you can decant the most of the unwanted stuff prior pitching.
One should produce as much yeast as is needed to ferment out the whole batch and then pitch as cold as the yeast allows.
A yeast growth in the fermenter shouldnt be targeted.

Cheers :icon_cheers:

I dont brew many lagers but when i do i do as zwickel has pointed out.

Pitch low and pitch big.

 

[Bribie G]

I've just had my road to Damascus thanks to you guys. Frign awesome:

Look at this:



currently I can get only 3 cubes into my lagering fridge side by side. However it never occurred to me but I can get at least 4 kegs - a keg will fit in front of the one you see in the pic. I can't quite get 3 across ( edit: photos are deceptive, no I cant unfortunately) so I won't get 6, but if I can get them to fit in the pattern of a 5 on a dice then I might just might get 5 in. In any case 4 would be a quantum leap, as well as 3 in the serving kegerator... it's nice to have three on tap but there is the option of two on tap and one lagering.

So I could hopefully have eight kegs all either lagering or being served.

Than opens up possibilities of stretching out the lagering to months instead of weeks, and get onto some of the 'better' liquid yeasts like Urquell, Danish whatever. Best OP I've made in yonks, thanks guys.

Now for the 4 keg purchase deal....... B)

Oh and yes I've been swung to the concept of cold pitching, also just bought a 5L demijohn from the LHBS which I should have done ages ago. Still working out how to do my stirplate with the magnets and fan that Bjorn sent me but I'm sure the demijohn will have an application as well, so big starters here I come :beerbang:

 

[gjhansford]

Look at this:

View attachment 33694

You've got it now ... I've got 6 kegs in the server, 5 in the lagering fridge and a spare two in my original small chest freezer. And I'm about to crack a dunlkelweizen that's now 3 months old :icon_drool2:

And for few bucks you can get one of those Bronco Faucets and try the lagering beers without moving them out of the fridge too much. :icon_cheers:

 

[Synthetase]

I wouldnt recommend that.
The yeast growth should take place outside the fermenter. At higher temps the yeast produces a lot of unwanted stuff, that all would be in your beer in the end.

If one likes to produce a clean lager or pilsener beer, let the yeast grow in a separate vessel, so you can decant the most of the unwanted stuff prior pitching.
One should produce as much yeast as is needed to ferment out the whole batch and then pitch as cold as the yeast allows.
A yeast growth in the fermenter shouldnt be targeted.

Cheers :icon_cheers:

Yeast growth in the fermenter is exactly what's occuring - albeit at a relatively slow rate. That's what microorganisms (any organism for that matter) do; they feed and reproduce. The reason it's slower is that fermentation is inefficient compared with aerobic (oxygen-requiring) respiration. Oxidative respiration of one glucose molecule will result in the production of up to 38 molecules of ATP (cellular molecular energy). The exact number of ATP molecules produced varies depending on the organism, suffice to say that a lot of the work unravelling eukaryotic energy catabolism has been done in yeast. On the other hand, the (alcoholic) fermentation of one molecule of glucose will yield two molecules of ATP.

This, of course is why you should make sure you have a good sized starter culture to begin with because fermentation is inefficient and growth is slow, a low number of yeast cells could be out-competed for resources by other contaminating organisms. This is also why brewers are encouraged to aerate their wort prior to pitching. The addition of oxygen allows the yeast to multiply quickly and establish themselves well before everything slows down (metabolically) during fermentation.

 

[cdbrown]

So is that let it finish out at 5C then in secondary for 5 days?

Yeah - basically it was in primary for about 10days dropping the temp down from 10C to 5C, then 5 days in secondary at 5C, which was enough for it to finish ferment. If going into keg as secondary then either leave it for longer to be sure it's done or connect a picnic tap and use the pressure built inside to push some beer out for sampling.

 

[Zwickel]

Yeast growth in the fermenter is exactly what's occuring - albeit at a relatively slow rate. That's what microorganisms (any organism for that matter) do; they feed and reproduce. The reason it's slower is that fermentation is inefficient compared with aerobic (oxygen-requiring) respiration. Oxidative respiration of one glucose molecule will result in the production of up to 38 molecules of ATP (cellular molecular energy). The exact number of ATP molecules produced varies depending on the organism, suffice to say that a lot of the work unravelling eukaryotic energy catabolism has been done in yeast. On the other hand, the (alcoholic) fermentation of one molecule of glucose will yield two molecules of ATP.

This, of course is why you should make sure you have a good sized starter culture to begin with because fermentation is inefficient and growth is slow, a low number of yeast cells could be out-competed for resources by other contaminating organisms. This is also why brewers are encouraged to aerate their wort prior to pitching. The addition of oxygen allows the yeast to multiply quickly and establish themselves well before everything slows down (metabolically) during fermentation.

mate, that all is well known over here.
The matter what were talking about is the production of unwanted stuff in lager or pilsener beers, such as fusel oils and fusel alcohols at higher temps. For some beer styles, mostly top fermenting beers, a certain amount of fusels is just wanted, because that is a carrier of some flavours, but not so for lager and pilseners. Having too much fusels in lager or pilsener beer would be a flaw.

That for it is highly recommended to decant the starter prior pitching, so you may pitch only dense yeast.

Cheers :icon_cheers:

 

[Thirsty Boy]

pitch low, pitch big -

Of course there is going to be some growth of yeast in the fermenter - but as zwickel rightly points out, a lot of flavour production by yeast occurs during its initial high reproduction rate phases... pitching more yeast means less required growth and cleaner flavours. Let the yeast do their too much of reproducing in your fermenter and you get the attendant flavours. Make a big enough starter, pitch only the thick slurry and minimise (to a point of course) the number of generations of growth required by the yeast before they slow the hell down and get on with fermentation rather than breeding. In a clean lager I target a pitching rate that I believe will give me about 3-4 generations of growth in the fermenter, to hit peak yeast cell count. That's where I think the flavours are at their optimum levels - clean and crisp, but not too clean and entirely without character. The more yeast character I want in the beer, the lower the pitching rate and the more generations of growth in the fermenter I want.

 

[Synthetase]

pitch low, pitch big -

Of course there is going to be some growth of yeast in the fermenter - but as zwickel rightly points out, a lot of flavour production by yeast occurs during its initial high reproduction rate phases... pitching more yeast means less required growth and cleaner flavours. Let the yeast do their too much of reproducing in your fermenter and you get the attendant flavours. Make a big enough starter, pitch only the thick slurry and minimise (to a point of course) the number of generations of growth required by the yeast before they slow the hell down and get on with fermentation rather than breeding. In a clean lager I target a pitching rate that I believe will give me about 3-4 generations of growth in the fermenter, to hit peak yeast cell count. That's where I think the flavours are at their optimum levels - clean and crisp, but not too clean and entirely without character. The more yeast character I want in the beer, the lower the pitching rate and the more generations of growth in the fermenter I want.

The "amount" of growth will not be affected by the inoculation volume/number of cells pitched, it is limited only by available resources. Therefore suppose that unfermented wort contained 1 mole of oxygen which allowed 10^8 yeast cells to multiply twice aerobically prior to induction of fermentation. This results in X aerobically-derived by-products being produced. A smaller number of cells would simply reproduce more times until the oxygen ran out and a larger number would do so less times - all of these would produce the same amount of aerobically-derived by-products because they are limited by the supply of oxygen. It is only the rate of multiplication that is altered by pitching size.

I'm confused as to why people seperate growth from fermentation. They are intertwined. Yeast multiply, it's what they do. It's all they do. Fermentation is merely a method of generating energy to achieve that goal. The only real difference between the two stages of initial oxidative multiplication and fermentation is the speed at which they do it due to the aforementioned inefficiency.

To clarify my original post, I fail to see anything wrong with pitching warm for two reasons: (1) It allows the yeast to multiply faster; and (2) done correctly, will not produce fusel alcohols because these are only produced during fermentation, not aerobic respiration. Therefore, provided you can lower the temperature prior to fermentation taking place, it will have no effect on the flavour of the beer.

 

[Jonez]

pitch low, pitch big -

.... Let the yeast do their too much of reproducing in your fermenter and you get the attendant flavours. Make a big enough starter, pitch only the thick slurry and minimise (to a point of course) the number of generations of growth required by the yeast before they slow the hell down and get on with fermentation rather than breeding. In a clean lager I target a pitching rate that I believe will give me about 3-4 generations of growth in the fermenter, to hit peak yeast cell count. That's where I think the flavours are at their optimum levels - clean and crisp, but not too clean and entirely without character. The more yeast character I want in the beer, the lower the pitching rate and the more generations of growth in the fermenter I want.

Interesting, however I now ask myself (Hope this doesn't come across as a stupid question): how do the commercial breweries keep their yeast always at optimum?. How do they limit the number of generations for example? I am guessing they must have some sort of very organised cultivation system. How do they produce generation zero for every batch?
cheers