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Old 02-20-2012, 08:55 AM   #1
Murray
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Default Lager Fermentation Question

Hi,

I brewed a lager beer last weekend, (OG1.045) and I used a pack of the Wyeast Czech Pilsner yeast (liquid activator - direct pitch). The smack pack had worked fine (swollen up nicely) at around 16-17 degrees C and I pitched it into the wort at around 15 deg C. The wort was very well aerated when I pitched.

My fermenter was in a fermentation chamber set to 6.5deg C (the recommended range for this yeast is 5-8, so bang in the middle). It probably took around a day to get down from 15 to 6.5.

I have not noticed too much bubbling from my airlock, and I did a gravity test and see the gravity is moving downwards (dropped to 1.040 after 6 days) but the fermentation is not nearly as strong as I would have thought. Also, I got a significant cold break, which has now all settled at the bottom of my fermenter, and so when I did my sample for my gravity reading, I got beer without the cold break stuff in it. (The cold break was obvioulsy all mixed in when I did my OG reading before fermentation)

Do you think my fermentation is "real" (ie the drop on gravity comes from fermentation) or from the fact my latest sample had no cold break material in it?

Does cold break material in suspension affect the gravity reading anyway? (Someone told me anything in solution affects readings, but things in suspension do not?)

Is this too slow for a lager fermentation? (I usually brew ales so have nto experienced this before)?

What should I do, if anything, to salvage this and get it going?

The beer is quite clear, the taste is very sweet obviously but has awesome malt flavours evident, and I really want to make this batch a winner.

What do you think?

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Old 02-20-2012, 09:17 AM   #2
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At that temperature fermentation is supposed to be slow, especially with the rather low pitching rates that we home brewers use as compared to commercial breweries. I personally ferment my lagers at around 10 °C and it takes me about 8 days to fully ferment an OG 1050 beer.

If anything, you might try pitching colder next time, as such a large temperature drop might shock the yeast and slow fermentation down, possibly even stop it altogether. Commercial lager breweries pitch at fermentation temperature and if anything let the temperature increase a little as fermentation starts. Maybe next time try cooling both the wort and the yeast down to 10°C before pitching, and then try to lower the temperature in the course of two to three days. Aerating only after the wort has reached 10°C is also a good idea, as you will get a higher concentration of oxygen.

What you have been told regarding solution vs suspension and specific gravity is correct.

Cheers,

Vale

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Old 02-20-2012, 09:29 AM   #3
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ok, then I think fermentation is happening, because I am seeing a drop (albeit a slow one) in gravity. I will give it another 5 or 6 days and see if it is still dropping, or has stopped.

If it were to have stopped, do you have a suggestion as to what I might do? Heat it up a bit, aerate/shake it about/pitch some more yeast?

Any help greatly appreciated

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Old 02-20-2012, 09:57 AM   #4
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Pitch more yeast. You really underpitched, IMO. People suggest two vials for a lager, and you are really on the lower end of lager yeast fermentation temperature so definitely more than a single vial. Throw another one on the fire ASAP.

and I think vale's suggestion of 10C is spot on for a lager.

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Old 02-20-2012, 10:18 AM   #5
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Quote:
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ok, then I think fermentation is happening, because I am seeing a drop (albeit a slow one) in gravity. I will give it another 5 or 6 days and see if it is still dropping, or has stopped.

If it were to have stopped, do you have a suggestion as to what I might do? Heat it up a bit, aerate/shake it about/pitch some more yeast?

Any help greatly appreciated
Definitely do not aerate or you'll get all sorts of off-flavors through oxidation. Gently stirring the yeast cake up can help, but raising the temperature is definitely your best line of defense. I'd raise to 10°C right away and then if necessary go all the way to the highest allowable temp for this type of yeast, as recommended by the manufacturer.

Besides higher temps, I found yeast nutrients a must for fermenting lagers. My personal preference goes to Servomyces, though a bit pricey they really speed fermentation up.

Cheers,

Vale
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Old 02-20-2012, 10:28 AM   #6
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Thanks Guys. I will raise temperature to 10C straight away, and will gently agitate the yeast cake to get things moving. I willl see if that works before pitching more yeast. The Wyeast activator packs are 100bn yeast cells and are pretty decent sized packs. If I don't get anything in a few days I will get another pack of yeast in there.

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Old 02-20-2012, 10:28 AM   #7
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Hi,

The beer is quite clear, the taste is very sweet obviously but has awesome malt flavours evident, and I really want to make this batch a winner.

What do you think?
This is definitely not a good sign, you want the beer to turn all cloudy during primary, which is a sure sign that the critters are really busy chewing on those sugars. It'll clear up nicely once they're done and you've cooled down to lagering temps. Crank that thermostat up pronto!

Cheers,

Vale
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Old 02-20-2012, 10:29 AM   #8
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Thanks Guys. I will raise temperature to 10C straight away, and will gently agitate the yeast cake to get things moving. I willl see if that works before pitching more yeast. The Wyeast activator packs are 100bn yeast cells and are pretty decent sized packs. If I don't get anything in a few days I will get another pack of yeast in there.
Incidentally, what size batch are you brewing?

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Old 02-20-2012, 12:58 PM   #9
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The batch is a shade under 20 litres, so about 5 gallons in a glass carboy

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Old 02-20-2012, 01:03 PM   #10
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At this point, there isn't much you can do except wait it out. Keep it at 50 degrees (F), and let it go. You need far more yeast than you pitched, but the yeast reproduce and then get to work. For your next lager, make sure you make a HUGE starter (consult mrmalty.com) and pitch just a shade under fermentation temperature and lit it rise to the desired temperature.

This time, since you are having some activity (SG falling), leave it alone! Don't swirl, raise the temperature, or otherwise mess with it. You'll have some off-flavors from the long lag time and pitching at a warm temperature, but that should fade with lagering.

Lagers are a bit more trouble- they need far more yeast than a single "smack pack", and they need strict temperature control. But they can be worth it!

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