Starters: Big or ramp?

[NoNothing]

Hey everyone.

I've always been a fan of making my starters large. For instance a 1.086 IIPA I'm making I've made a 3.5L starter from an American Ale 2 smack pack. I expect 360b cells. A hair over what's required for the beer. I'll save ~50b by vol for another starter.

Is there any benefit when going from that 50b to 2-300b in ramping the starter size up? Why not start at 2-3L? What advantage is there to doing 500ml, 1.5L, 3L?

 

[BigFloyd]

Using a stirplate?

 

[NoNothing]

Using a stirplate?

Yes, sorry.

I always use a stir plate and 1L/100g water/DME concentration.

 

[specharka]

In short, yes.

The way microflora propagate is they rapidly expand in population until either the number of active cells reaches a terminal cell density (usually around 1-2 billion per milliliter for S. cerevisiae) or the expanding cell population exhausts their biological reserves for growth. Depending on wort aeration, this growth factor will vary, but the yeast will get stressed with a growth factor greater than 5. So if you start from a saturated yeast colony, there's no benefit to adding more wort than the expected yeast population is able to consume.

This is a really important lesson when you build starters from bottle dregs, where the initial cell count is diminutive. Not only will an improperly sized starter have a longer lag phase, but the additional time may allow the chance for bacteria or wild yeast to take over. So ramping the starter size up gradually is an essential element to good yeast management techniques.

Tl;dr use a 2-step starter for standard yeast pitch sizes (e.g. 800 mL, 4L) or a 3-step starter for small yeast populations (e.g. 50 mL, 250 mL, 1L)

 

[NoNothing]

Thank you I'll start making smaller starters and growing them.

Should I chill the initial starter and pour off as much spent wort as I can before stepping up? Or just add the difference between the two amounts in fresh wort?

 

[kombat]

3.5L is "large?" Hope you don't plan on brewing lagers.

I rarely make anything smaller than a 5L starter. I always just use a single smack-pack or vial, and I use a stir plate. The last starter I made was a 5L of Munich Helles lager yeast. The yeast took 2 days to get going, so to ensure they were healthy, I decanted the spent wort and fed them 5 more liters. It's cold crashing in my fridge right now and I'm brewing tonight.

I believe the literature says to step up your starter volumes by factors of 10, and I admit my method is probably not optimal.

 

[NoNothing]

3.5L is "large?" Hope you don't plan on brewing lagers.

I just started looking into lagering as I've finished my fermentation chamber. Holy crap do I need a lot of yeast.

I just got a package of Czech Pils but it's from Sept '15. I've got it on 500ml to see if I get any activity and I'm pretty sure it's dead and I'll be brewing a pale with some left over American Ale 1.

 

[DurtyChemist]

A stepped starter will result in the yeast cells being more saturated than one large starter. If you start with 1 billion and grow 50 million yen you're pitching 150 million into another liter. The book Yeast covers this and recommends a 10 fold increase in stepped starters and not just a 4-5 fold increase. Stick with making a single 3.5 L starter unless you plan to remove most of the yeast cells at each step. I'd trust the book Yeast on information of yeast stress more than someone saying saturation is harmful then telling you to add a little bit more wort and result in a lower growth rate and terminal cell density.

 

[kombat]

Give it a little extra time. The Munich Helles lager yeast I mentioned rode my stir plate for 2 full days with 0 activity. I checked the gravity, it was unchanged at 1.041. I turned off the stir plate, but didn't have time to dump it and clean the flask until the next day. When I came down to empty it, it had suddenly started fermenting.

That said, yeast that old will need to be built back up.

 

[NoNothing]

I didn't plan correctly. I think I'll just make a pale and build this up and chill it and brew with it in next weekend or so.