High Gravity Lager Starter Advice

[kingmatt]

I am planning on brewing a 1.096 OG Doppelbock soon and was hoping for some advice on how to best achieve my target pitch rate (apprx 800 billion cells).

I have a stir plate and a 2000ml and 5000ml flask.

Am I better off pitching 1 vial into a smaller starter and stepping up (several times) or pitching 2 vials into a large starter?

I generally brew ales so I confess to having limited knowledge of the effects of growth rate when stepping up starters and the various pitch rate calculators online have yielded different results.

Input from someone more knowledgeable on yeast propagation and/or high gravity brewing would be much appreciated!

 

[JonM]

I'd make a half batch of a Pilsner lager or something and use that yeast rather than make a gigantic starter that would just go down the drain.

 

[kingmatt]

I'd make a half batch of a Pilsner lager or something and use that yeast rather than make a gigantic starter that would just go down the drain.

Yeah, I don't really have time for that as I hope to have the Doppelbock ready by early February.

I have a Munich Helles fermenting now and thought about using the yeast cake from that brew for my Doppel but I was hoping to use a different yeast (used 34/70 for the Helles and want to try the Wyeast Hella Bock for my Doppel)...

 

[helibrewer]

It's all about inoculation rate when propagating yeast.

One new vial (96% viability) in a 2L starter with aeration will yield about 377 billion cells (2.92 growth factor). The inoculation rate on this is 48 million cells per ml.

The same vial in a 5L starter will yield about 800 billion cells (7.34 growth factor). The inoculation rate on this is 19.2 million cells per ml.

Lower inoculation rate = higher growth factor.

So the numbers say a fresh single vial in 5L should give you ample yeast. You might also consider doing a viability starter and adding it once active fermentation begins.

Here's a great tool: Yeast Calculator

 

[kingmatt]

It's all about inoculation rate when propagating yeast.

One new vial (96% viability) in a 2L starter with aeration will yield about 377 billion cells (2.92 growth factor). The inoculation rate on this is 48 million cells per ml.

The same vial in a 5L starter will yield about 800 billion cells (7.34 growth factor). The inoculation rate on this is 19.2 million cells per ml.

Lower inoculation rate = higher growth factor.

So the numbers say a fresh single vial in 5L should give you ample yeast. You might also consider doing a viability starter and adding it once active fermentation begins.

Here's a great tool: Yeast Calculator

Thanks for the input! Isn't a high growth rate like that detrimental to the yeast? I thought I read that a growth rate of over 3 can affect attenuation?

 

[helibrewer]

Not that I am aware, it is more to do with physical/nutrient limitations of the solution

 

[schematix]

I think you have plenty of time here. 2-3 months is enough even for a big lager.

I prefer to save the $8 and start with 1 vial and just add a step to the propagation process. DME cost is about $1 per 1L of starter and I think it results in a more vibrant culture.

But to your main question:

I'd either use the entire cake from your helles (just pitch right onto it)

or

Do a multiple step starter: Use your 1 vial into 1L and then crash and decant that. Pitch that slurry into 2L... crash and decant that. Then either make a half batch of something you want to drink and use the cake form that, or go ahead and make a 4L starter, then use the cake from that. You could even take the slurry from the 4L and split that into your 2 flasks, feed them again, then save the smaller one for a future batch.

Don't get too hung up on the calculators and numbers. They're a Wild Ass Guess anyways. Just do 3-4 steps of starters or 3 steps and a small batch.

 

[kingmatt]

Thanks for the responses. Looks like I should just save myself the time and money and pitch onto my Helles cake. I guess it would be hard to over-pitch on a beer this big anyway...

Anyone brewed a Doppelbock with 34-70 that turned out well?

 

[schematix]

I'm sure you'll be fine.

I've used half a dozen different lagers yeasts and honestly the differences are so subtle that you'd be hard pressed to identify a different one in a random sampling. Yah some are a little more diacetyl, green apple, or sulpur prone, but it's not like night and day differences you can get with ale yeasts.

34-70 is pretty neutral anyways. Quantity of healthy yeast is whats most important here.

 

[specharka]

Thanks for the responses. Looks like I should just save myself the time and money and pitch onto my Helles cake. I guess it would be hard to over-pitch on a beer this big anyway...



Anyone brewed a Doppelbock with 34-70 that turned out well?

Yes, I brewed one that turned out quite well despite initial turbidity issues (did not rack to secondary for lagering). You will probably need 2-3 satchets and a starter to get where you want to as far as pitching rates go. I used 2 with a 3000 mL starter and had fermentation activity within 18 hours.
Definitely want to start the beer very low (~48F) and gradually bring it up to diacetyl rest temperatures after 10-14 days. I would not want to try warm fermentation at that high of an OG, you will risk making a butter bomb.