How much slurry should I get from a 2L starter?

[wmlynch]

I've just made my first starter from a WLP001 PurePitch pack that was produced on 5/1/15. I made 2L 1.040 wort and shook it intermittently for 48 hours before crashing it in the fridge for 24 hours (I'm going to brew tomorrow morning). It seemed to ferment pretty well with a nice krausen formed and the hydrometer reading I just took was down to around 1.010. It smells fairly yeasty and still has a good amount of solids in suspension (I was expecting more to drop out...).

My question is how much slurry should I end up with at the bottom of my pitcher? I've got a layer about 1 cm thick and I just want to make sure that I'll be pitching enough into my beer tomorrow. Thanks!

 

[Yooper]

I've just made my first starter from a WLP001 PurePitch pack that was produced on 5/1/15. I made 2L 1.040 wort and shook it intermittently for 48 hours before crashing it in the fridge for 24 hours (I'm going to brew tomorrow morning). It seemed to ferment pretty well with a nice krausen formed and the hydrometer reading I just took was down to around 1.010. It smells fairly yeasty and still has a good amount of solids in suspension (I was expecting more to drop out...).

My question is how much slurry should I end up with at the bottom of my pitcher? I've got a layer about 1 cm thick and I just want to make sure that I'll be pitching enough into my beer tomorrow. Thanks!

Crashing for 24 hours is probably not long enough- it may take longer for the majority of the yeast to fall out as WLP001 isn't particularly flocculant (I believe White Labs says "medium") but it's slow as a rule.

 

[wmlynch]

Crashing for 24 hours is probably not long enough- it may take longer for the majority of the yeast to fall out as WLP001 isn't particularly flocculant (I believe White Labs says "medium") but it's slow as a rule.

Ok thanks. It'll probably get another 24 hours in the fridge before I'll need to pitch it tomorrow anyway.

 

[wmlynch]

So how much slurry should I expect to see once it's fully flocc'd?

 

[Qhrumphf]

You'll want to pull that yeast out of the fridge, decant off the spent beer, and then give it time to warm up. You don't want to pitch fridge temp yeast slurry into pitching temp beer, too big of a temperature gradient that can shock and negatively impact your yeast. You want the yeast to be close-ish to the batch wort temperature. I pull my starter out of the fridge when I start brew day (all grain, so ~5 hours prior to when I'll be pitching, if you're brewing extract you may want to do it earlier), decant, and let it sit out while I brew to slowly warm back up. So factor that into your time considerations.

Also, a 2L starter of 3 week old yeast is going to be a pretty large amount of yeast. Without knowing the batch size and gravity, we can't determine how much yeast you need, but that's often a med-low gravity lager or high gravity ale pitching rate for a 5 gallon batch.

 

[wmlynch]

You'll want to pull that yeast out of the fridge, decant off the spent beer, and then give it time to warm up. You don't want to pitch fridge temp yeast slurry into pitching temp beer, too big of a temperature gradient that can shock and negatively impact your yeast. You want the yeast to be close-ish to the batch wort temperature. I pull my starter out of the fridge when I start brew day (all grain, so ~5 hours prior to when I'll be pitching, if you're brewing extract you may want to do it earlier), decant, and let it sit out while I brew to slowly warm back up. So factor that into your time considerations.

Also, a 2L starter of 3 week old yeast is going to be a pretty large amount of yeast. Without knowing the batch size and gravity, we can't determine how much yeast you need, but that's often a lager or high gravity ale pitching rate for a 5 gallon batch.

Sure I understand about warming it up. I'm not going to warm it until tomorrow when I need it. I made the starter 3 days ago and it fermented for 2 days. It's not 3 weeks old, the yeast was packaged 3 weeks ago.

When you decant the liquid how much slurry do you end up with is my question?

 

[flars]

A 2 liter starter with 7.2 ounces of DME and yeast produced on 5/1/2015, should yield approximately 373 billion cells.

 

[wmlynch]

A 2 liter starter with 7.2 ounces of DME and yeast produced on 5/1/2015, should yield approximately 373 billion cells.

200-300ml of slurry sound reasonable?

 

[Qhrumphf]

Sure I understand about warming it up. I'm not going to warm it until tomorrow when I need it. I made the starter 3 days ago and it fermented for 2 days. It's not 3 weeks old, the yeast was packaged 3 weeks ago.

When you decant the liquid how much slurry do you end up with is my question?

I mean the original yeast was 3 weeks old, which is pretty fresh by at least the standards of my LHBS. This results in a higher resulting cell count in the starter than if the starting yeast was older. The point is there's a fairly high number of cells in there.

Go to http://www.mrmalty.com/calc/calc.html or http://www.yeastcalculator.com/. This will tell you the number of cells that you need for your batch.

You've got approximately 232 billion cells in your starter (per YeastCalc using the JZ intermittent shaking growth figures, which is what you did). What you need to do is figure out how many cells you need, decant off most of the spent beer, leaving a little behind, and then use an appropriate portion (or even all depending on the beer).

For your average ale, you want 0.75 million yeast cells per milliliter per °Plato of your batch. For lagers you want to double the rate to 1.5 million cells.

 

[wmlynch]

I mean the original yeast was 3 weeks old, which is pretty fresh by at least the standards of my LHBS. This results in a higher resulting cell count in the starter than if the starting yeast was older. The point is there's a fairly high number of cells in there.

Go to http://www.mrmalty.com/calc/calc.html or http://www.yeastcalculator.com/. This will tell you the number of cells that you need for your batch.

You've got approximately 232 billion cells in your starter (per YeastCalc using the JZ intermittent shaking growth figures, which is what you did). What you need to do is figure out how many cells you need, decant off most of the spent beer, leaving a little behind, and then use an appropriate portion (or even all depending on the beer).

For your average ale, you want 0.75 million yeast cells per milliliter per °Plato of your batch. For lagers you want to double the rate to 1.5 million cells.

I used the same yeast calc and that's exactly the number I was after. I'm trying to determine if I hit that number by estimating the volume of the slurry.

 

[Qhrumphf]

If you don't have a hemocytometer, don't bother trying to estimate. These growth curves were meticulously measured by people doing starters and then counting cells (although JZ/Chris White and Kai Troester came to different growth curves). They'll be more accurate than your eyeball guesstimate of slurry volume.

 

[wmlynch]

I looked up some photos online of yeast starters after cold crashing and mine looks pretty similar, so for future reference or in case someone has the same question, yes a 1cm layer of slurry at the bottom seems about normal.

Thanks for the input.