Cold Fermentation method keeps failing me (stalling)

[Techbrau]

Don't bother doughing in lower than 62c. There's no advantage and the nasty oxidative enzymes are more active at the lower temps. Just add 1-2 grams of wyeast nutrient at the end of the boil.

[Nick_D]

[Weizenberg]

I often use yeast nutrients. It's more convenient than doughing in thick and all that

[Weizenberg]

[Bilsch]

Something tells me in my case there may be more to it than just zinc. I have dosed many batches with an average of 0.074mg/l of ZnSO4*H2O and saw little improvement in fermentation performance. One recent beer I even pitched 5 very fresh packs of yeast and the result was the same sluggish under attenuated ferment that I had to keep bumping up the temperature to save from stalling.
I’m sure the water here has a big part to play as it comes from mountain snowpack a few miles down the road. It is devoid of pretty much everything and it gets an RO polishing to boot. Most other municipal water sources contain nitrates which might actually beneficial to yeast health. Maybe there is varying nitrogen content in the malt lots based on how it was grown? This residual nitrogen content is certainly a factor in cider fermentation depending on how the trees were fertilized so why not barley?
Anyway these experiences are anecdotal evidence at best but nothing made much improvement in yeast performance until adding the nutrients. It might be the synergy of the nitrogen and zinc or other things in there, I don't know for sure. I can tell you though my latest batch of helles on 2206 with the WY magic powder is marching strong at 7c and is one healthy ferment.

Thanks to Bryan and the short course at TUR for this nutrient tip. Also many thanks to the members here on the inspiration for the glorious malt bill:
80.8% Pima, 9.7% Vima, 5.1% Muma, 2% C25, 2.4% AM

[Weizenberg]

Agreed. Nutrients are the simplest solution. For large outfits it can become quite expensive, but what do we care!

FYI one can influence FAN with mash as well (dough in at 35C). It won't be as effective as nutrients.

[Bilsch]

[Nick_D]

Sure wish I'd thought of the nutrient thing prior to my recent brew..... now I'm nervous It may become another sink dumper... but hopefully not! I guess if it was easy, everyone would be brewing amazing German lagers. Nothing worth doing is ever easy, as they say !

[Owenbräu]

You'll get FAN in most good yeast nutrient, too. However, it's very unlikely that FAN is the issue. Yeast will absorb ammonia as a nutrient (DAP), but it is likely bound to chlorine to form chloramines long before it comes out of your tap.

You also have to remember, that zinc limitation is mostly a concern when pitching cone to cone for many generations. Yeast grown in an all-malt starter will have access to plenty of zinc.

Have you all tried letting the ferment ramp up to 8-9C around day 3-5? This is still acceptable as a cold fermentation profile. Narziss warm is 10-11C.

[Nick_D]