Overbuilding Imperial yeast starter

[McMullan]

It's important to note that higher temperature increases the rate of yeast growth, but not necessarily the final yeast count, which is fixed by other factors. I don't make bigger starters for lagers, but I do build them up from small beginnings and pitch fresh, when viability and vitality are highest. Then I'll repitch at least 1-2 times. Nor have I found it necessary to pitch more (lager) yeast for pressure fermentations, either at low lager fermentation temperatures or at 'ale' temperatures. Although far from an expert on lagers, I prefer them fermented at lower temperatures, under a little pressure or not. I'm more interested in naturally carbonating during fermentation.

 

[renstyle]

I ran with Homebrew Dad's overbuild calculator.

My 2001 was from late February, so I considered it 55% viable for starter calculations.

I ran with the basic specs:

Pitch rate - 0.75million/ml
Batch Volume - 5.55gal/21L
OG - 1040 OG
Overbuild - 105 billion

Only a single step, 1.5L/164g DME. After 30-ish hours on the stir plate in 1040 wort, the calculated cell count is in the 284 billion range.

I crashed the flask, decanted a bit off the top, then swirled up the rest such that I had 2 pint jars. Since I was only looking for 105 billion cells per pitch and may have potentially gotten in the 140 range, I'll consider that a good "safety margin".

There was a delay between starter creation and brew day, so I needed to crash the whole shebang knowing I'll need to do extra steps to "wake up" the pitch for the BoPils.
Built a vitality starter with one of my pint jars, maybe 900mL. It was a lazy brew day, so it had a full 5 hours to do its thing. First time trying this with a pint of my own yeast, pretty cool!

Brew day came and went. Started the spund @ 12 PSI maybe 8-10 hours after sealing up the corny keg.

FG per the recipe was 1.007. Right now at about 70 hours in, we are at 1.009-1.008, which could be it for this one.

I did a free rise from 18C, it's currently at 21.1C and rising. My inkbird cutoff is 22C, but I wondered if the off-gas now at 12 PSI is just due to the uptick in temp? I am in the "forever bubble" stage, one every 15 seconds due to the 8mm EVA barrier tubing I am using for the blow off.

I will likely call her done tomorrow and cold crash this one. The hydrometer samples were Saaz'y spicy!

 

[renstyle]

It's important to note that higher temperature increases the rate of yeast growth, but not necessarily the final yeast count, which is fixed by other factors. I don't make bigger starters for lagers, but I do build them up from small beginnings and pitch fresh, when viability and vitality are highest. Then I'll repitch at least 1-2 times. Nor have I found it necessary to pitch more (lager) yeast for pressure fermentations, either at low lager fermentation temperatures or at 'ale' temperatures. Although far from an expert on lagers, I prefer them fermented at lower temperatures, under a little pressure or not. I'm more interested in naturally carbonating during fermentation.

I am new to the process of starters. Just did my first "vitality" starter with my own "produce" as it were, albeit with a crash in between.

Do you have a post which explains your ideas further? I am intrigued, as I should prolly have all of the hardware needed to give what you suggest a try down the line.

I do pressure fermentation with lagers (now) as a result of my choice to ferment in kegs from the very beginning, so a spunding valve was near the top of my wishlist. Knowing this was a possibility from the outset made my initial purchasing decisions a bit simpler, and I can't complain. My ferm chamber is quite capable of traditional lager temps, as is the keezer, but figured why not give this spunding thing a go eh?

Did a single "traditional" BoPils last summer: 11C/52F for 3+ weeks while I was out of town. Pitched 2 sachets of 34/70 and let it roll in the keezer. It worked well.

Curious to see how 2001 performs under pressure (no pun intended).

 

[renstyle]

Day 1 of cold crash, hydrometer sample. Made it to 1.007.

Its not yet ready for serving, agree 100% on 1-2 weeks cold lagering in the serving keg will help smooth it out.

It has saaz spice bite, similar to what i get from an imported P.urquell, so good there.

Its not even fully reached crash temp (6C/42F) now at 12C/54F and falling. Should clear up well.

 

[McMullan]

Do you have a post which explains your ideas further?

It's just about preparing fresh yeast, with the highest cell viability possible.