Yeast starter health

[BlackRock]

A couple days ago I put together my first two starters in prep for a couple batches I'm planning to do this weekend.

I boiled up 2 cups of DME in about 11 cups of water to split between two different yeast starters. I chilled the wort to around 62* and split it between two half gallon jugs. I then pitched in one smack pack of London ESB for an upcoming Black IPA and an American II in the other jug for another round of our current favorite IPA.

In about two hours both starters were bubbling away. The next morning they were going really good but when we got home last night they'd stopped bubbling already and it looks like most of the yeast has dropped out.

I'm probably just worrying too much but I figured they'd have kept going for at least another day or so? I'm assuming they just ate all the sugar already but it's only been a day. It just seems like they finished up too quick.

Anyway, just wondering if that's what's to be expected? Also, I don't plan to use them until maybe tomorrow and Sunday, but I don't expect that should be a problem. I was also thinking of chilling them a bit to help drop out more yeast and then decant most of the fluid off the top before pitching into my beer.

What say you Beer Brewing Masters?

 

[chickypad]

It's very likely done - my starters finish in about 24-30 hrs on a stir plate. I'd go ahead with the plan to stick in in the fridge then decant and pitch when ready.

 

[BlackRock]

Excellent. Thanks Chickypad. Your timeframe of 24-30hrs is pretty spot on to what I saw. I started with the Wyeast packs and smacked those a few hours before pitching in the starters and both were plump and healthy when I pitched those.

You have a guess as to how many yeast cells I've grown? The smack packs start with the 100B cells and I fed each 1 cup of DME in 1200ml of water. I've seen people use everything from a quarter cup to a half to one cup or more of DME but I haven't found any good info on determining how big a starter you get based on what you fed it. Just the basic 10g of DME per 100ml of water.

 

[Pie_Man]

The starter is likely done, or nearly done. Keep in mind you pitched an entire package of yeast into a very small amount of wort.

Many people like to shake/stir the starter multiple time to help grow the yeast cells. You'll notice that mrmalty.com shows that intermittent shaking grows more cells versus a simple starter. For this reason, I find it's better to do this without an airlock on the starter vessel, instead using a sanitized piece of tin foil.

 

[Pie_Man]

I haven't found any good info on determining how big a starter you get based on what you fed it. Just the basic 10g of DME per 100ml of water.

It depends on the OG and the age of the yeast package. i'd recommend mrmalty.com or yeastcalc.com for determing starter size.

 

[chickypad]

i'd recommend mrmalty.com or yeastcalc.com for determing starter size.

^ This. With really fresh yeast you probably about doubled your count to 200 billion, but you can plug in your own numbers.

I use the 10g per 100ml because it's easy to remember and measure and gives you the proper gravity (about 1.035 to 1.040).

 

[BlackRock]

Great info. Exactly what I was looking for. I'll look up both of the sites.

Also, I've swirled/shaken both starters a number of times over the last day and a half and the yeast cake is a good inch+ thick. Hopefully I've got some really big starters going. One is for my 7% IPA and another is for a Black IPA that will hopefully hit 8.3% or so.

 

[Pie_Man]

Cool, good luck. Yeastcalc is nice because it allows you to do multiple step starter. If you think you need a larger starter size with the high gravity beers, you can play around with using a second starter step to boost your cell count.

I'm guessing your 8.3% abv black ipa may require a slightly larger starter, but I'm estimating. I would guess the beer's OG is around 1.078 and you probably have about a 1.1 to 1.2 liter starter now. Even if the yeast was very fresh, the calculations I get show you a little short of the desired yeast cell count.