Avice: Take a look at my yeast starter

[berrywise]

I am brewing a Russian Imperial Stout with an estimated original gravity of 1.108. Using Wyeast 1056 and a 2L starter Beersmith calculates 417 billion cells (and it calls for 394 billion to be needed).

This is the first time I've brewed a big beer so I have always done 1L yeast starters. I popped it on the stir plate for just shy of two days before dropping it in the fridge last night to let it settle out for today's brew day.

This morning I was a little dismayed that there didn't seem to be nearly as much yeast settled in the bottom as I thought there would be. This is about what I usually see in my normal 1 yeast starters (which I normally go for 24 hours). That said I can't recall the last time I used 1056 so not much to compare there.

Am I being paranoid? RDWHAHB situation? Or should I be hitting up the homebrew store on lunch break

Thanks!

advice...avice....can't edit the title.

 

[max384]

That yeast cake looks small to me as well, for a 2 liter starter. If it were me, I'd probably decant, and step it up with another starter wort to be safe. 1.108 is a big beer, and I'd rather err on the side of too much yeast, rather than too little. YMMV though.

 

[IslandLizard]

The age of and # of viable cells in the yeast pack makes a difference to growth and final cell count. It looks like a decent amount, but may not be enough for your RIS.

Now you cannot add 2 liters to this slurry after decanting and hope for some magic growth, the wort will be saturated already. Use about 60 billion cells from this slurry (estimate 1.5 billion cells per ml of pourable slurry) which will grow in that 2 liters to 354 billion. Add some from your first starter and you'll be good, while you'll have some left over for another batch or starter.

Do you plan to oxygenate the wort? I would recommend it especially at that gravity. With good oxygenation you may have enough cells already.

 

[berrywise]

If it were me, I'd probably decant, and step it up with another starter wort to be safe.

Now you cannot add 2 liters to this slurry after decanting and hope for some magic growth, the wort will be saturated already. Use about 60 billion cells from this slurry (estimate 1.5 billion cells per ml of pourable slurry) which will grow in that 2 liters to 354 billion.

Do you plan to oxygenate the wort? I would recommend it especially at that gravity. With good oxygenation you may have enough cells already.

That was my first thought was to just decant, make up some new wort and let it start building again. Maybe I just got a smack pack with not much oomph in it.

I realized I still had a can of that Wort in a Can that Northern brewer uses so I'll use that up. Nice in a pinch for when I don't want to boil wort this morning.

IslandLizard I'm a little confused by what you wrote. I should be able to just add new wort to my existing cake right?

As for oxygen I don't have O2 but I do have my fish pump with built in filter I planned to run on this as well as some good old shakes to mix it up.

 

[Weezy]

I think lizard is saying don't put new starter on top of that much slurry. All that slurry will just eat the new wort without growing many new cells. (I could be wrong tho). Decant off about 2/3 of that slurry and keep it in a different jar.

 

[flars]

Follow the advice of @IslandLizard for estimating the number of cells per milliliter of yeast and using only some of the yeast for the new two liter starter.

Put your numbers into this calculator. A warning pop up will show when the starter wort is being innoculated with too many yeast cells for an optimum growth rate of new cells.
http://www.brewunited.com/yeast_calculator.php

 

[max384]

Standard practice for stepping up a starter is to decant and add new wort on top of the existing yeast cake. New cells will still grow. It may not be quite as efficient as doing multiple starters... But it's far more convenient to only have to pitch from one starter.

 

[berrywise]

I think lizard is saying don't put new starter on top of that much slurry. All that slurry will just eat the new wort without growing many new cells. (I could be wrong tho). Decant off about 2/3 of that slurry and keep it in a different jar.

Follow the advice of @IslandLizard for estimating the number of cells per milliliter of yeast and using only some of the yeast for the new two liter starter.

Put your numbers into this calculator. A warning pop up will show when the starter wort is being innoculated with too many yeast cells for an optimum growth rate of new cells.
http://www.brewunited.com/yeast_calculator.php

Aha, yep that make sense. I'll put some in a sanitary mason jar and set aside. Good call.

Thanks all!

 

[IslandLizard]

Aha, yep that make sense. I'll put some in a sanitary mason jar and set aside. Good call.

Thanks all!

That's the idea!

Thanks to all of you for filling in!

Regarding oxygenation, definitely aerate well! I'd do 1/2 an hour with the pump before pitching and an hour (or 2) afterwards.

Also look up vitality starter (brulosophy.com started this, and there's been plenty of feedback and discussion). This maybe a good occasion for it, in addition to aerating (or oxygenating) well.

Here's my slightly modified version of this.
Use 2 liters of your wort at 1.040. Easiest is to use second and/or third runnings, they're close already. Adjust to 1.040, boil in a pot, chill and add to your decanted slurry, allowed to warm up to room temperature (do this a few hours ahead. Then spin for 2-4 hours while brewing your batch. Or put in a gallon jug with the yeast and shake vigorously till very foamy. Keep doing that every 20-30 minutes. Before you shake, open the lid and run some fresh air into it with your pump. These methods makes the yeast very viable, ready to go for pitching. Pitch the whole jug's worth, don't crash or decant.