Lager fermentation time

[verysupple]

Hi All,

My first attempt at a lager is fermenting right now. It's the AG version of the Vienna lager from BCS. Everything I've read regarding lager fermentation suggests that they take a fair bit longer than average ales to start and then ferment out. But mine had krausen within 12 hours and was at about 80 - 85 % of the expected attenuation after 3 days. So I started raising the temp for a diacety rest and it should be at FG in a day or so I guess. So this is only about a day longer than my average strength ales. Of course I'll let it condition for a bit before I drop it to lagering temps.


Here are the specifics:

OG 1.052
Expected FG 1.012 - 1.014

Made a stepped starter of Wy2308
Oxygenated by shaking the FV for about a min.
Took the starter out of the fridge, decanted the beer and pitched the cold yeast into the wort at 9 C.
Pitched something like 1.5 - 2.0 million cells / mL / P (about 20 - 25 million cells / mL) depending which calculator you believe (slightly higher than I intended because my final volume was less than I anticipated).
Let free rise to 10 C where I kept it until I started the diacetyl rest.


And now for the point of the post.

Firstly, is this abnormally fast considering the temperature?

But more importantly, is such a fast fermentation likely to cause any problems down the line? Stability issues etc? I was thinking about repitching some of the yeast for a Munich dunkel after this batch, so is this pitching rate high enough to make the average age of the population quite old because they didn't multiply much? Would I be better off taking a small amount and propagating it so the population is nice and young again?

And for a small rant. When people say things like, "I ferment my lagers for 3 weeks" I'm guessing they really mean they let them sit in the fermentor for 3 weeks, becuase a healthy fermentation of an average strength lager shouldn't take anywhere near that time. Fermentation is the process of converting sugars to gases and alcohol, and is not the same as conditioning/maturation. Get the terminology right.

 

[DJ_L3ThAL]

My first (and only) lager was with w34/70 and it fermented out at 12C in 3 days, beer turned out fine. I pitched two packets so think the people who say lagers take longer may be under pitching instead of pitching 2x that they would for an ale... happy to be corrected but it seems you've done everything you can to deserve a healthy vigorous fermentation

 

[micbrew]

I put down a lager ..last year
I did open a bottle a few weeks later ......much to early

from my little experience ...time is the key
let it sit and all will be fine

I must research me another lager or two to put down

mick

 

[Black n Tan]

I don't think it is too unusual. I haven't used that yeast but I usually hit FG within 5-7 days. A vigorous ferment is desirable to drive off sulphur compounds so I think it is a good thing. I tend to leave mine at diacetyl rest temps for 5 or so days as yeast clean up better at elevated temps and then cold crash for 3 days and into the keg to lager. I typically get it into the keg in less that 2 weeks and my lagers have down well in comps so I know it works. So yes they take a little linger than ales, but not much longer if you pitch a large healthy starter.

 

[sp0rk]

I've got a lager on at the moment, it took about 5 days to hit FG and I did a D-Rest for 3 days once it had almost hit the FG
It's been lagering for 4 days now and I'll be transferring to keg some time next week
off topic, any problems with lagering on the yeast cake?

 

[mje1980]

The last few lagers I've done I've pitched lots of yeast cold, into cold wort, and they've hit fg in around a week. They've also tasted much better than any of my other lagers.

I pitch at around 7-8, let rise to 10. I have one in the primary at the moment, which is around 5 weeks, but only because I'm in a leg splint and it is kind of hard to lift stuff at the moment. I plan on leaving it there for another 2 weeks, then just keg. Otherwise I would have given it a secondary. I've just today started dropping the temp, slowly to 4c ish for the next 2 weeks.

Boring side fact, it's a xxxx gold clone with 2042, cluster and dextrose :0. Sample tastes malty sweet, and on the dry side (1.005 fg ). With some carbonation i think it'll be quite nice. I'm putting a Belgian pils on the yeast cake. Again, I'll take a huge whack of slurry, put it in the fridge with the other cube of pils overnight, then pitch cold.

 

[verysupple]

Thanks everyone, it's good to know things are going fine.

So what's the opinion on repitching? Is it worth propagating again or should I just rinse and repitch the required amount?

 

[DJ_L3ThAL]

If youve got enough and its straight away then rinse and repitch. Rinsing may also have minimal benefit?

 

[verysupple]

If youve got enough and its straight away then rinse and repitch. Rinsing may also have minimal benefit?

I'd pitch the yeast the day after it was harvested. I'd only rinse it to minimise the amount of trub in the mixture so I could make a better estimation of my pitching rate. I'm not too worried about the trub affecting the fermentation or flavour. I was more worried about the vitality of the yeast given that they probably didn't multiply much in the current batch and so probably have lower than ideal vitality.

 

[DJ_L3ThAL]

Yes but you can adjust for non yeast material in your slurry with the calculator which is easier than rinsing... either way your still guestimating to an extent and neither is more "accurated" than the other if you get my drift?

 

[verysupple]

Not all guestimates are equally accurate. I find it much easier to estimate the percentage of non-yeast material after rinsing because I can see the separate layers in the test tube (it's actually a measurement but it's not very accurate - so I called it an estimate).

Every batch of beer is different so I really don't trust the calculator when it comes to the non-yeast percentage. Imagine 100 mL of unrinsed yeast slurry from a heavily dry hopped IPA and 100 mL of unrinsed slurry from a blonde ale. The consistency may seem the same so you'd use the same setting in the calculator. But you know the non-yeast percentage must be different. Rinsing should level the playing field a bit. In any case, at least if I rinse using the same method every time I will be consistent relative to myself (which is what matters). It doesn't matter if I don't know the number of cells, I just want to be able to pitch either more, or less, or the same amount as the last time I brewed that beer. I mean, I have a microscope, haemocytometer, and alkaline methylene blue so I can measure the cell density and viability (but not vitality) if I want, I just usually can't be bothered.

To each their own I guess. Everyone should do what they're comfortable with.

Anyway, none of this addresses the vitality issue. Has anyone had problems repitching yeast from a batch with such a high pitching rate?