Fermentation temp experiment

[12PACFan]

I'm getting fairly confident in my brewing with ales and somewhat confident with lagers. I wanted to start experimenting with various aspects of the process to see what I can tweak and improve on. Fermentation temperature is fairly easy for me to control so I decided to try a black lager, but with a fermentation temp twist. I started with an all grain mash and my wort ended up at SG 1.056. I pitched SafLager W-34/70 German Lager Dry Yeast from a 1L starter at 60 degrees F then once activity was evident, I dropped the temp down to 40 over the course of 36 hrs. Activity slowed, but the airlock was active throughout the drop down and remained active once at 40. I plan on raising temps back up to 60ish as SG gets lower for a diacetyl rest and to chew up any remaining sugar.

It's been chugging for a week now, but I don't live at the place I brew, so I haven't been able to check SG. I'll get that tonight and give a progress update.

I know this isn't the normal lager method, but was curious what I might expect for a finished product. Anybody do something similar? Keeping steps as simple as possible, would anyone do anything different? Before everyone chimes in and tells me I waisted a perfectly good batch, even bad beer makes for great brat boils.

Thanks for the feedback

 

[Jack Arandir]

W34/70 is a super forgiving yeast strain. I would expect it to turn out very well. I don't see anything crazy about your fermentation-- 40F is rather cold for primary, but 34/70 can handle it.
* You probably don't need a diacetyl rest with that strain; Weihenstephan goes directly from primary (50F) to lagering (32F) without raising the temp.
* A 1L starter probably didn't do much for you-- you increased cell count by ~50% while using up some of the yeast glycogen reserves, so roughly a wash. Maybe next time just pitch two packs or do a 3-5L starter.

All in all, you'll probably turn out an excellent lager. Let us know how it tastes.

 

[12PACFan]

Thanks for the feedback. Checked the SG tonight after 5 days and it is down to 1.04 with activity in the airlock, so nothing fast, but steady. Couldn't help but give it a quick taste and was surprised by the lack of "yeast" flavor. I know it will continue to develop, but off to a great start.

Do you think I gained anything with the cold ferment? Would a ferment at 50F produce a similar clean taste?

 

[Jack Arandir]

Some German breweries use cold ferments: pitch 42F, ferment 46F. It slows down yeast activity and develops different flavors. So I don't necessarily object to your cold primary. I'm planning to try it for an upcoming Munich Dunkel.

A 50F primary would be slightly different, but maybe not enough to taste the difference. 40F just slows down your process. You'll probably need another couple days before you hit FG. With some yeasts, you risk stalling the yeast by dropping it too low. But with lager yeast in general and 34/70 in particular, that should not be an issue.

That said, every strain has its temperature where it's happiest. Manufacturers post it on their spec sheets. Brewers dial in their cultures and learn what temperature gives the best results. The sweet spot for 34/70 seems to be in the mid to high 50s according to the manufacturer. Weihenstephan uses 10C (50F) for primary.

One German brewing process I'm interested to add is "maturation". At ~60% attenuation, rack the beer off the yeast into a lagering vessel (kegs in my case) with a spunding valve. Lager 5+ weeks and let the beer naturally carbonate. It's supposed to develop finer carbonation and more refined flavors.

 

[Northern_Brewer]

As others have said, 34/70 is very forgiving, you may want to check out this Fermentis article where they see little difference between 12°C (54°F) and 16°C (61°F) and not much more with 20°C (68°F) :
https://fermentis.com/en/news/fermentation/rediscover-saflager-w-34-70/
There's a whole long thread about using lager yeast at "ale" temperatures - and more :
https://www.homebrewtalk.com/threads/warm-fermented-lager-thread.592169/

 

[Kickass]

Do you think I gained anything with the cold ferment?

Extra time to wait for your beer to finish. That’s likely all you gained.



This is a really good podcast with a representative from Fermentis talking about temps, pitch rate, and gravity when using 34/70.

Spoiler: you can ferment it warm and unless you’re a more sensitive taster than fermentis trained tasting panel, you’ll never notice a difference.

 

[VikeMan]

I'll just mention (again) that the Fermentis study concluded that measurable levels of certain compounds were similar for beers fermented between 54 and 68F. So it compared warm fermentation to warmer fermentation, and not to traditional truly cold lager fermentation. It makes one wonder why.

 

[Bobcatbrewing42]

I'm getting fairly confident in my brewing with ales and somewhat confident with lagers. I wanted to start experimenting with various aspects of the process to see what I can tweak and improve on. Fermentation temperature is fairly easy for me to control so I decided to try a black lager, but with a fermentation temp twist. I started with an all grain mash and my wort ended up at SG 1.056. I pitched SafLager W-34/70 German Lager Dry Yeast from a 1L starter at 60 degrees F then once activity was evident, I dropped the temp down to 40 over the course of 36 hrs. Activity slowed, but the airlock was active throughout the drop down and remained active once at 40. I plan on raising temps back up to 60ish as SG gets lower for a diacetyl rest and to chew up any remaining sugar.

It's been chugging for a week now, but I don't live at the place I brew, so I haven't been able to check SG. I'll get that tonight and give a progress update.

I know this isn't the normal lager method, but was curious what I might expect for a finished product. Anybody do something similar? Keeping steps as simple as possible, would anyone do anything different? Before everyone chimes in and tells me I waisted a perfectly good batch, even bad beer makes for great brat boils.

Thanks for the feedback

Sounds ok. Your start temp sounds high to me. I shoot for a pitch a couple of degrees over optimum ferment temp from the manufacturer (usually 52-54) and let it cool. Banana flavored lager is bad to me. Colder, say in the 40's seems to shut it down. I just watch the ferment and when it slows, do a few days D-rest at 65 ish, until bubbling stops, then chill. I don't recall any off flavor notes on my score sheets with that method.