Starter calculator for cultures

[baer19d]

Does anyone know of a calculator to determine how big of a starter to make when making one from a slant? I've been just making starters based off the size I would make if I were using liquid yeast but I don't know if that's correct.

 

[gkeusch]

I am struggling with this too. I think the calculators assume a certain number of viable cells in a yeast pack or vial as a starting point, and I don't know how that correlates to starting from a slant and stepping up. Not having a microscope, I have looked through the literature and it seems that there is general agreement (if there ever is such a thing with brewers) that there are about 1.2 to 1.5 billion cells per millimeter of slurry in a typical starter. So I have been crashing my starters and measuring the amount of slurry in the bottom. So if one is shooting for about 200 billion cells for a 5 gallon batch with a middle-of-the-road gravity and uses the 1.2 billion number, then the required volume of slurry for pitching is 167 ml., or about 3/4 cup (6 oz.). I have a heck of a time amassing this much slurry in a two liter starter.

So I hope somebody can help us.

 

[baer19d]

I don't even come close to that much slurry in a 2L starter. In fact, compared to the pitchable packs from White Labs I only have a fraction of what in them. Maybe they put a lot more cells in their packs to account for the loss during the 6 month shelf life.

 

[Oginme]

I plate my yeasts and when starting them back up I typically use about 10 ml to 20 ml of 1.020 gravity wort (usually from DME) and put about 5 to 10 of the bigger colonies in it. I will then step it up to 200 ml to 250 ml of standard 1.038 gravity wort before moving to a full sized starter. This gets me to 200 billion cells or slightly greater by my counts. I don't cold crash or decant starter between the first and second step, but just pour the initial "wake up" starter into a 1 liter flask with the 200+ ml of starter for the second step.

 

[lslbrew]

I use the one at brewers friend.com. For starting cell count I use .001. I use a "glob" off my slant and put in 200 ml then step up to 1800 ml. The rule of thumb is to step up 10x so go from slant to 1/10th the final starter size up to about 500 ml. Over that it is hard to get a good growth from slant to +500 ml

 

[FermentedCulture]

https://suigenerisbrewing.blogspot.co.uk/2012/11/yeast-banking-iv-starter-tables.html

 

[baer19d]

.001 seems to be a useful starting point. When I use this number as the starting cell count in BeerSmith it tells me I need a 1.8L starter which falls in line with the typical 2L starter for a higher gravity (1.068 in this case) 5 gal. batch.

 

[baer19d]

Thanks, this is very useful. I recently watch all of this guys videos on Youtube and they were very informative.

 

[baer19d]

https://suigenerisbrewing.blogspot.co.uk/2012/11/yeast-banking-iv-starter-tables.html[/QUO
According to Beer Smith I need about 260 billion calls for the gravity in question (1.068/5 gal). According to this chart I'll get 380 billion if I do the second 1.5L starter, 120 billion more than I need. I wonder if I just do a 1L starter for the 2nd starter (3rd step) if that would get me closer to the required 260 billion?

 

[paneubert]

I don't even come close to that much slurry in a 2L starter. In fact, compared to the pitchable packs from White Labs I only have a fraction of what in them. Maybe they put a lot more cells in their packs to account for the loss during the 6 month shelf life.

You can pull the quality control and actual cell counts for each White Labs batch. For the three I pulled recently, each was sitting at 3.8 billion per mL. Their acceptable range is from about 1.5 to 4 billion per ml. It is probably wise to assume that a clean home-made starter made with just fermetables and no hops is going to be much more yeast dense than "slurry" harvested from a finished ferment and will probably be closer to the White Labs numbers.

While the 4 billion is a commercial concentration and higher than seen in most home-made starters, I still think 1.2 to 1.5 billion cells per millimeter of slurry is on the low end of typical/average, assuming someone decants their starter well before swirling and measuring and assuming they did not have a lot of extra "bulk" to dilute the concentration.