I’m about to start my Fall and Winter Lagers starting with my Octoberfest. So what’s the secret to making great Lagers. Low and Slow , lots of patience and lets not forget temperature control. All yeast strains have a temperature range under which they give optimal fermentation results. With most lager strains this temperature range can be anywhere from as low as 38 degrees to as high as 60 degrees. So keep the temperature in the best optimal range for the strain your using to ferment your Lager. Diacetyl(2,3-butanedione) is produced by all yeast during fermentation, but is usually reabsorbed by the yeast cells. Non-reabsorption or over production is caused by feeble or short boiling, low temperatures during fermentation, mutated yeast, or racking too soon. It can also be formed by bacteria contamination. Always boil vigorously for the appropriate amount of time. Raise your temperature slightly as you near the end of fermentation. This helps the yeast reabsorb diacetyl. I always do a Diacetyl rest. The process is simply to raise the fermentation temperature from lager temperatures (50° to 55° F) to 65° to 68° F for a two-day period near the close of the fermentation. Usually the diacetyl rest is begun when the beer is two to five specific gravity points away from the target terminal gravity. The temperature is then lowered to conditioning temperature following diacetyl reduction. To test for diacetyl i like to use the “diacetyl force test
Pull a sample or two from your fermentor (in as sanitary a fashion as possible, obviously) into your glasses – it doesn’t need to be a huge sample, but not too small either. I usually reckon on about 50 – 100ml. Cover with foil. Put one of the samples aside somewhere safe at room temperature. Using a water bath (this can be as simple as a bowl of hot water), raise the temperature of the other sample to between 60 and 70 degrees centigrade and hold it there for 10 to 20 minutes. This heating will force any (flavourless) acetolactate present to change into diacetyl, which we can taste and smell. After heating, cool the sample back down to room temperature (an ice bath is ideal). You can now assess both samples for diacetyl. If you notice it in both, then you have a lot present in the beer and it will certainly need a good diacetyl rest. (This may also indicate a bacterial or wild yeast infection, but don’t panic yet!) If you only notice it in the heated sample, then you have acetolactate present – if you rack the beer now, it is likely to turn into diacetyl over time, so be patient, let it rest some more, and maybe consider raising the temperature. If there is no discernible diacetyl in either (or at least, not more than is appropriate for the style), you can rack and bottle your beer with confidence! Log into Facebook | Facebook
Thank you for that excellent explanation and information!
Any tips for bottling? What temp and do you repitch yeast?
All good advice. Its a couple months before I start my lagers again ( I brewed my Octoberfest back in March) but I have been following a similar schedule using German ale yeast in my lager recipes at a little warmer temperatures. Still do the d-rest as well. Quite pleased with the results.
Good stuff Damian! Saw it on your FB earlier today.
Bottling is identical to ales. You can repitch lager yeast, no problem. Done it many times.
I’ll reprise a photo of my German Pilsener from a few years back when I was bottling, really one of my best early efforts…
Pretty beer
Do you bottle at lager temperature? Or bottle before lagering?
My approach is to ferment at typical lager temps, raise temp for DA rest, then bottle. Once bottle conditioned at room temperature*, extended time at cold temps provides clarity and crisp flavor.
*I think some of the confusion comes from what to do with lager yeast when it comes time to bottle condition, typically 2-3 weeks at room temperature. The tiny fermentation that occurs to carbonate a bottle doesn’t have significant impact on final product. Colder temps would lead to a much slower and possibly incomplete carbonation.
Sorry been busy week. My approach to bottling a lager is little different than Voodoo’s after my D-rest I purge my head space with CO2 then I bulk crash the whole brew still in the fermenter. This improves your clarity and a lot less sediment in you bottles. The purge Co2 will protect it from oxidation. The co2 is dissolved back in to the beer crashing so when your ready to bottle use the highest temperature you beer fermented at your D-rest temperature and calculate your priming sugar for that temperature. As for repitching your yeast as long as you had a healthy fermentaion and the Abv is not to high. Repitching is a great way to save money and plan multiple brew with the same yeast.
Thank you Danny. I thought i would post it here to for those that don’t have facebook or hadn’t followed the page
This was great! Thank you
arrrggg…i’m out of pils and that looks sooo tasty!
Now when would be a good time to dry hop. During the d-rest or after during the cold crash
I personally would during the D Rest. But I’ve dry hopped a lager at 50° with success. Contradictory advice anyone? 
Agree with @loopie_beer, D rest would be perfect for getting the most out of the dry hop, followed by a cold crash.
This differs from my lager bottling recommendation above due to the turbidity and “chaos” that occurs with dry hopping; cold crashing would be advisable in this scenario, especially with bottling. Kegging ?
I always wait till after the D-rest and test to dry hop. It makes it easier to detect any Diacetyl
I admire your completeness in testing for diacetyl, probably a good idea now that you’re a pro as well as a homebrewer. Having to dump 200 gallons or more of lager wouldn’t be great. I guess I’m lazy or have just been lucky so far…Diacetyl in my beers is kinda like Sasquatch to me, I’ve never detected it…But it could be out there!
I know some beers are infamous for it, ?Pilsner Urquell, Innis and Gunn, Samuel Smith’s, and of course Chardonnay.
I always do a thourough diacetyl(often longer than even recommended) rest with lagers when within a few points of anticipated Terminal gravity, and it seems to work. Denny Conn even does a DA rest with ales…
In my experience DHing in the keg, when looking for big nose in an IPA the best results tend to come from DHing at room temp prior to chilling. I don’t think I’ve ever DH’d a lager…
@voodoo_donut a little diacetyl is true to style in a pils isn’t it? Can’t say I’ve ever noticed it in any Urguell I’ve had and thankfully not in my own pils either.
