Advantage to building up a starter in steps?

[tidehouse]

I've read that you can step up your starter by increasing sizes but is there any advantage to doubling up a starter from, say, 1 quart to a half gallon to a gallon as opposed to just pitching the yeast right into the gallon jug?

 

[FlyingHorse]

Fourteen Essential Questions About Yeast Starters

Q: When increasing a starter in steps, should the steps be a certain size?

Yes, but there is plenty of leeway in the size of the steps. A “step” is when you take an active starter and increase the volume with more wort. Brewers do this to increase cell mass, while keeping the rate of growth consistent.

The size ratio of one step to the next can affect the health of the yeast and the amount of cell growth. A very large step can result in a change in yeast metabolism, where the sugars that are fermented last can fall out of favor with the yeast. The yeast become lazy and subsequent generations can become lower attenuating.

Making a greater number of small steps increases the chance of contamination. Every transfer, every feeding, every bit of handling you do increases the chance of contamination. Five to ten times the size of the prior step is considered correct. You should try to balance the practical considerations of handling, sanitation, and cell growth.

 

[b767fo]

Making a 1 gal starter in a 1 gal jug..I am still scraping junk off of my stir plate. Two 2qt steps makes a lot less mess...

 

[smakudwn]

What about a smack pack? could'nt you just pitch that to a 2 liter starter?

 

[Saccharomyces]

A smack pack can go straight into any size starter you wish up to about 3 gallons because there is plenty of viable yeast.

What you want to do is step no more than 5-10x the number of yeast cells. So when I start from a slant, I will innoculate about 1 cup of sterile wort on the plate which will build up about 25B cells, and then from there I'll go to 1.5L which will give me about 200B cells. If I were to go from a slant to a gallon starter (I'd need one of those 5000mL mega flasks for that, which I don't have) I would do 1 cup, 1.5L and then 4-5L to stay within the 10X growth maximum.