Yeast Starter size - Beersmith2

Hi,

I am using Beersmith 2.0 to design a hybrid recipe. I am stuck on the "yeast starter tool" section.

I am using Wyeast 1007 (German Ale yeast) in a propogator pack (the small packs which have 25bn cells, designed for making a starter with). The manufacture date was 16 May 2011.

On the Wyeast pack, it says that if you grow that yeast in a starter of DME (up to 1.06OG) for a few days, you will generate enough cells to ferment a 5 gallon batch.

I am making a 30l (8 gal) batch. When I put this information into Beersmith, it tells me I need 23 yeast packs for the starter! This is clearly crazy.

The recipe calculates I need 384bn yeast cells. It also calculates a yeast viability of 22.79% given the yeast I am using and the manufacture date. I figure one of these is wrong, because the yeast propogator packs contain 25bn cells and that is all that I see in the formula. There are other inputs in the "yeast starter options" but I have left them all at default numbers.

How many packs of the Wyeast do you think I should be making a starter with? I am making 8 gallons of hybrid ale. (1.052OG, 1.014FG)

Your definitely going to need to step your starter. I'd start here YeastCalc
With your smackpack being so old, you probably want to start with about a 500 ml starter and step from there.

Just use mrmalty.com. Beersmith 2.0 is a train wreck.

Thanks Sulli. So, from the YeastCalc it tells me my yeast viability is 10%. From Beersmith it tells me the viability is 23% (seems yeastcalc just steps down to 10 after about 3 months, while Beersmith has soem formula). Assuming we think the "real" viability is 20% (just used an average), I have fudged the production date to 07/29/11 to get a yeast viability of 20%.

My first step takes 75bn cells @ 20% viability (15bn viable) and with a starter volume of 2 litres gets me to 93bn after step 1. If I add this to a fresh starter of 3 litres I get to the 300bn cells I need for fermentation. (30 litre fermentation, OG1.054).

This make sense, but soe practical questions :

What OG do I make my starter wort in eachof these steps? Sure this affects yeast growth? I see the link says 1.037. Is that the way to go?

How long do I leave it for each step?

Do I pour off the liquid between steps when I add fresh wort ? If I use a stirrer plate, presumably I wait for things to settle out before decanting off my spent liquid?

It looks like I am going to need 2 steps to get to my cell-count. how do I think about te volume of starter for each step?

There is a link on the YeastCalc page called "care and feeding of your yeast", it will give you the information you seek. Happy brewing.

Just something I thought up here that I thought I knew, but now questioning.

If step 1 is 1 liter, then I decant to about 1 inch left over yeast then do I had 2 liters of wort in the 2nd step to make a total of 3 liters (1 decanted, adding 2), or do I add 1 more liter (1 decanted,adding 1)?

This is just going off what looks like the default YeastCalc settings. Starter size in step 1 if 1 liter, starter size in step 2 is 2 liters.

The way I read the article suggested you add your yeast to 1l wort in step 1, then decant your wort after letting it settle in the fridge. Now you are left with a slurry and a tiny bit of wort. You add 2 l of cooled new wort to this slurry mix. That process is consistent with the yeastcalc settings of 1l step 1and 2l step 2 I think.

Yes, the starter volume is the amount of new wort added to the starter.
Even if you don't decant, the volume entered for the next step should only be the amount of new wort added. But in that case you would have to adjust the gravity of the next addition to account for dilution of the sugars from the previous volume of fermented wort. This tends to complicate things, which is why I always just decant the spent wort from the previous step.
Clear as mud, right?

For my batch this weekend I have tried the techniques on the YeastCalc website and it has worked very nicely. I think I used to let my starters sit for too long in the past (ferment out completely), and then chuck the whole thing into my fermenter at pitching time (with sometimes quite a lot of aerated, spent starter wort). I have had great activity with the step method, and the refrigeration between steps to accelerate the yeast settling out is a great idea. Step starters are the way forward. Finishing my final step and when I brew on Friday I will only be adding the slurry and as little wort as possible.

Thanks for the pointer to yeastcalc ! I never took pitching rates that seriously before. This batch will see about 9mm/ml. I must admit my previous batches were probably in the region of 2 or 3mm/ml !

Excellent! I'm glad you had such good results. Let me know how your beer turns out.

Wow, last night did my decant and added my second starter volume of wort. I was worried as hell when I decanted because I thought I as pouring all the yeast out (even though I let it settle for 24h in the fridge). I added he fresh wort and aerated and went to bed. This morning we have more action I the flask than I have ever seen in a starter preparation before. Looks like a really healthy and aggressive starter. I shudder when I think of how I have been pitching yeast before. To anyone who doesn't make use of the step starter technique, try it. It takes mildly more time, but is definitely worth it I think.