Propagating Saflager 34/70 using low gravity ale fermented at ale temperatures

[artichoke]

Hi,

I have a packet of Saflager 34/70 that I'd like to propagate quickly up to a large enough pitch for 12 gallons of a 1.050 lager (~850 billion cells according to the MrMalty online calculator).

A pitch of 850 billion cells would require approximately 4 packets of dry 34/70, or alternatively, a gigantic 12L starter. Given these are somewhat expensive options, and if were to make a starter I'd do it at room temperature anyway, I'm seriously considering just pitching my one packet into a low gravity, 6 gallon ale recipe fermented at normal ale temperatures ~ 65-70F to prop the yeast. The advantages being that I could prop up the yeast quickly and fill an empty keg with a quick (and hopefully) delicious ale as a by-product.

I have no concerns that the starter ale will farm the yeast I need, and the farmed yeast will work just fine for a true lager. However, will the resulting starter beer be drinkable, or will there be off flavours as a result of fermenting the 34/70 at such high temperatures?


Thanks,

- Artichoke

 

[didinho]

Hi,
I have no concerns that the starter ale will farm the yeast I need, and the farmed yeast will work just fine for a true lager. However, will the resulting starter beer be drinkable, or will there be off flavours as a result of fermenting the 34/70 at such high temperatures?

I had very bad experience withh lager yeast fermented too high, around 16-18°C. a lot of phenols and plastic-like flavour. But it was a bavarian lager by wyeast, never tried the saflager at such temperatures...
if you're lucky it just comes out fruity with esters

 

[NTexBrewer]

http://brulosophy.com/2015/06/22/fermentation-temperature-pt-3-lager-yeast-exbeeriment-results/

Here is an interesting read about lager yeast at higher temps.

I think you should be fine but I would ferment the ale at the lower end around 63 degrees. Make sure the wort is aerated well and consider using yeast nutrient for both batches.



I do something similar to what you are proposing but do all of the fermenting at lager temperatures. I brew a 5.5 gallon light lager OG 1.046 using 2 packs of 34/70. Harvest the yeast and then make two 2.5 gallon bigger beers. I currently have a 2.5 gallon batch of Doppelbock OG 1.086 and a 2.5 Gallon Pumpkin Lager OG 1.062 fermenting from the last time I brewed the light lager.

 

[Hujo]

Like the others have said, just try to keep the temp down and you'll be fine. 34/70 is pretty tolerant IME.

 

[schematix]

Make a simple 1.040 beer and pitch your 1 pack around 58-60F.

 

[artichoke]

So I finally got around to brewing the 34/70 "yeast starter" on Saturday. I used Biermuncher's fabulous Cream of Three crops as the inspiration for the recipe because I wanted minimal beer flavour impact to the harvested yeast, and more importantly it makes a really delicious beer when done with S05.

OG was 1.050, calculated IBU's ~13. Pitched 1 re-hydrated packet of 34/70 in ~ 21L wort, set the fermentation temp control to 60F and by yesterday evening fermentation was underway.

Everything looks normal so far, and no horrible off aromas are currently being generated by the fermentation. I'll update the post in around 3-4 weeks when it's kegged to report back with the results.

- Artichoke.

 

[artichoke]

Update, I just kegged the 34/70 "starter".

Here's the recipe and some measurements I took throughout the process. 21L into fermentor, ~ 73% efficiency.

Grain bill (basically, Cream of 3 crops but a bit bigger)
.96 kg Gilbertson and Page 2-row (rest of bag)
2.04 kg Weyermann Pilsner
1.0 kg O-I-O flaked maize
0.58 kg white minute rice (rest of box)
0.14 kg Best Malz Acidulated malt

Milled above together and mashed in 12L strike water @ 162F in mash tun. Added 4.2 g CaCl2 to mash. Note that Vancouver BC water is very close to RO.

- 90 minute mash, measured Mash T was ~ 150F at end of mash. Measured PH at end of mash / sparge = 5.32

- Fly sparged and collected 31L wort

- 90 minute boil

- 60 mins, 7g Magnum pellets @ 13.7% AA for ~ 13 IBU

10 mins, 1/2 tsp white labs yeast nutrient

10 mins, 1 whirfloc tablet

chilled and siphoned into glass 24L carboy, 21L into carboy, ~ 40 sec pure O2

OG = 1.051, post boil pH = 5.20

- pitched 1 pkt re-hydrated Saflager 34/70

Fermented in chamber for 7 days @ 60F

remainder of fermentation @ ambient basement temp, approx 62F.

FG = 1.004, ABV ~ 6.2%. Final pH + 4.34.

Impressions:

Not the lager-ish flavour I was expecting. Visually, a bit murky as well. Despite the low FG, quite fruity and sweet tasting, malty and a somewhat viscous mouthfeel. I suspect this is diacetyl although I am certainly not an expert in off flavours. Could also be the booze that's contributing to the sweetness.

That said, as a yeast starter the slurry should be good to use (collected about 1 L nice slurry) as there are no off contaminated flavours and obviously fermentation went well. Not great warm and flat but not terrible or undrinkable either. In any case, I'm going to carb it up and serve it to some BMC lovers this weekend and see how it goes.

- Artichoke