# Lager Yeast - Slow Fermentation



## whitegoose (12/3/11)

So I'm currently fermenting a Vienna Lager (using Wyeast 2308 Munich Lager), which will be only the third lager I've brewed.

Today is the 14th day it has been fermenting, and the gravity has wandered down from 1.046 to 1.026 in that time, and over the last week I have slowly raised the temp from 10 degrees up to 11 degrees. 

My question is it normal for lagers to take this long? At this rate it will be sitting in primary for 4 weeks by time it is finished. Common sense says that the colder fermentation will cause the yeast to work slower, but isn't this kind of temperature what the lager yeast love?

I made a starter, and there is evidence of krausen in the fermenter. Another point of note would be that the gap between aerating the wort on it's way into the fermenter and when I pitched the yeast after cooling was probably 6 hours.

Any advice, common or contrasting experiences appreciated.


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## whitegoose (13/3/11)

Anyone?


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## vykuza (13/3/11)

G'day Goose. I used Munich for half a dozen brews last year and didn't see work that slowly, even as low as 9c. Maybe you've hit the nail on the head there with the delay after aeration, and it's struggled to get numbers up to work through all those sugars.

I think you've done the right thing (well, you've done what I would have done) in raising the temperature a notch and monitoring it. As long as it's still moving it's ok. Perhaps with a very well sanitised spoon you can give it a stir and get some of the yeast back in to suspension. Don't introduce more oxygen though, as it's too late for that now.

Good luck!


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## manticle (13/3/11)

Haven't used that yeast but lagers are usually slower. Those of my experience would be 2-3 weeks primary (closer to 2 most often but I don't stress if it's longer).

Cold temps are not necessarily what the yeast prefers, they are what will produce the most desirable profile. You could ferment at 20 degrees and the yeast would be totally happy. You might not be with the resulting beer though.

When it gets to around 1018 or so, slowly warm up to 16-18 for a diacetyl rest. This will also help finish it off a bit quicker.


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## Dave70 (13/3/11)

I had the same experience with doing lagers playing it by the book.
These days if I want a lager, I'll buy one.
I really couldn't be arsed with alll the waiting around when I've allways prefered ales anyway.


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## whitegoose (13/3/11)

Thanks guys... for a diacetyl rest, how long would you want to leave the temp at 16-18?


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## manticle (13/3/11)

I'd leave until you hit FG. Most of the ester production etc is done by that point. 

Once FG is hit, I believe the proper way to go about things is to drop the temp very slowly until you get to lagering temps. Normally I would rack to secondary before the diacetyl rest (which will encourage the yeast a bit more anyway). Alternatively you could rack just before lagering.

By the time you have hit lagering temps, the beer should have had some time at FG for conditioning.


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## mika (13/3/11)

It varies a bit, but ~2hrs after areation your Dissolved Oxygen levels are basically nothing.
The other thing you've got going against you, 10C is pretty cold even for a lager, I usually wouldn't go below 12C unless I was experimenting.
Then I'm guessing that your starter wasn't big enough, you probably needed a good 4L starter for that beer or the equivalent amount of slurry, especially if you pitched cold.
Don't worry too much for this one, 2308 is a hardy yeast and it will get there, just may take some more time.
Usually you wouldn't worry too much about the diacetyl rest if you pitched in at 10, though given you've probably stressed the yeast, a day or two at higher temps may help it out.


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## unrealeous (13/3/11)

whitegoose said:


> Another point of note would be that the gap between aerating the wort on it's way into the fermenter and when I pitched the yeast after cooling was probably 6 hours.


Am I reading you are aerating warm/hot wort - then cooling to pitching temp? What temp do you do your transfer?

The solubility of oxygen in wort temperature dependent - the warmer it is - the less soluble - so perhaps you are not getting your oxygen levels up to the desired 8-10ppm.


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## whitegoose (13/3/11)

unrealeous said:


> Am I reading you are aerating warm/hot wort - then cooling to pitching temp? What temp do you do your transfer?
> 
> The solubility of oxygen in wort temperature dependent - the warmer it is - the less soluble - so perhaps you are not getting your oxygen levels up to the desired 8-10ppm.


I go from kettle-->plate chiller-->aeration-->fermenter in one continuous line... on this particular day (perth summer) the plate chiller only got the temp down to about 30 degrees or so, and then it took another 6 hours to cool down to 13 degrees in my fermentation fridge...


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## unrealeous (13/3/11)

whitegoose said:


> I go from kettle-->plate chiller-->aeration-->fermenter in one continuous line... on this particular day (perth summer) the plate chiller only got the temp down to about 30 degrees or so, and then it took another 6 hours to cool down to 13 degrees in my fermentation fridge...


Using an additional form of aeration other than 'splashing' is certainly something you could try for your next attempt.

Once I reach pitching temp - I hook an aquarium pump (~$20) up via an inline air filter to the fermenter tap, and let it bubble away for 20 minutes or so. Always get nice vigorous fermentations this way. Others also give it another hit of oxygen at the 12 hour mark.


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## warra48 (13/3/11)

Depending on the time of year, I can get the immersion chiller to drop my brew to between 18 to 25C.
The fermenting fridge drops it down to about 10C by that evening or early next morning.
I'm a believer in pitching the slurry from a starter of at least 4 litres, and pitching it a t the same temperature as the wort.
I aerate with an aquarium pump, the same method unrealous uses.
I ferment my lagers at 9 to 9.5C, and leave them for 3 weeks. You need to have patience to ferment lagers at these temperatures. I'll then let it rise to about 15 or 16 for a couple of days, although I don't think they need a diacetyl rest with my pitching/fermenting method. I regularly achieve or exceed the theoretical Apparent Attenuation figures for the yeast I use. For example, my last brew I used WY2124, and achieved 75% as against 71% theoretical average.
I rack to another container for lagering.


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## Nick JD (13/3/11)

I pitch my lager yeast according to Wyeast's directions. 
_
__*Usage
*
The Activator™ package contains a minimum of 100 billion cells in a yeast slurry.. The Activator™ is designed to directly inoculate 5 gallons of standard strength ale wort (1.034-1.060 SG) with professional pitching rates. For lagers, we recommend inoculating the wort at warm temperatures (68-70F/ 20-21C), waiting for signs of fermentation, and then adjusting to the desired temperature. Alternatively, for pitching into cold conditions (34-58F/ 1-14C) or higher gravity wort, we recommend increasing this pitching rate. This can be achieved by pitching additional Activator™ packages or by making a starter culture. Please see the Pitch Rate section for additional information._

_*Instructions for the proper use of Activator™ packages:*_


_To activate, locate and move inner packet to a corner. Place this area in palm of one hand and firmly smack package with the other hand to break inner nutrient packet. Confirm inner packet is broken. _
_Shake the package well to release the nutrients. _
_Allow package to incubate and swell for three hours or more at 70-75F (21-24C) or immediately direct pitch into wort. _
_Use sanitizing solution to sanitize the package before opening. _
_Shake well, open and pour Activator™ into five gallons of well-aerated or oxygenated wort at 70-75F (21-24C). *Maintain temperature until fermentation is evident*: by CO2_ bubble formation, bubbling airlock or foaming on top of wort.
_Adjust to desired fermentation temperature. _
_
_

I do the same with dried lager yeast. Pitch in the early 20s and set the fridge to 12C. By the time the wort has cooled into the late teens, the yeast has bred up. Around the time it's 12C it's fermenting happily. I couldn't imagine how much yeast you'd need to pitch into a 10C wort - a lot. Why bother with a starter when you can make that starter in your fermenter?


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## SJW (30/3/12)

Nick JD said:


> I do the same with dried lager yeast. Pitch in the early 20s and set the fridge to 12C. By the time the wort has cooled into the late teens, the yeast has bred up. Around the time it's 12C it's fermenting happily. I couldn't imagine how much yeast you'd need to pitch into a 10C wort - a lot. Why bother with a starter when you can make that starter in your fermenter?


I know this is an old thread but it popped up on a Google search I was doing.
A friend was telling me the exact same thing yesterday......_Why bother with a starter when you can make that starter in your fermenter_ 300 billion cells is about whats required for 20 litres of Lager wort, so I would think that a std Wyeast would at least tripple in size during fermentation so there u go.


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## manticle (30/3/12)

The point of a starter though is to add the right amount of cells at the beginning, not to grow them slowly during fermentation so you have the right amount for the beginning at the end.

Supposedly it has an effect on ester production and too few cells at the beginning can lead to stalling etc.

You may not personally find that and if it works for you, then it works for you but the idea of growing cells in the full volume of wort misses the (possibly theoretical) point of what a starter is trying to achieve.

Add to that the idea of adding an active starter and it's a whole different ballgame.

If your friend's theory were sound you could split a yeast pack 5 or more ways without stepping up or making starters and the beer would behave and taste the same as using the full pack or making a starter.


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## black_labb (30/3/12)

I've made starters in the fermentor then pitched the rest of the wort on top of it. Obviously the starter is going to be part of the brew so you want it to atleast be similar. I usually do this with some wort that a rescue from the trub by cooling and decanting after some time. I'll then pitch from a cube onto it. 

Very simple and easy as you don't even have to sanitise a second vessel. The only extra work is reboiling the wort for sanitising and cooling it back down.


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## crd0902 (30/3/12)

I think this is along the same lines. I just keggeda coopers lager with s23 and as I had a Coles lager can i gotta use I thought I'd just reuse the yeast straight away rather than farm it and split into three ect. So I washed it a few times and ended up with a nice jar full of slurry added it to a 700 ml bottle with cool boiled water, brewed the batch, pitched the yeast about 21C, put in fridge about 8 hrs later she bubbling nicely but smells pretty off. Not the normal s23 smell. Is the yeast or could it be the Coles tin. Of course I'm gonna wait and let it finish and see how it is but just wondering

Cheers chris


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## SJW (30/3/12)

Hey Chris, lager yeast does throw a sulfur smell. Its all good.


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## crd0902 (30/3/12)

SJW said:


> Hey Chris, lager yeast does throw a sulfur smell. Its all good.



Yeah I've smelt it plenty of times with a fresh pack of yeast but this is the first time I've reused a yeast cake and it smells different. AlmOst sour. But cheers I'll see how it turns out. If it ain't growing green ill drink it


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