Settling time for yeast starter in Refrigerator?

[timsch]

I've got a 3L starter for an Oktoberfest (yeah, I know, a bit late for the season) that was on the stir plate for 4 days, and has been in the fridge for another 4 days. I want to decant most of the liquid off, but I'm thrown off by how cloudy it still looks. I don't want to pour off any of the yeast. Would that still be yeast in suspension, and if not, what would it be?

I've left starters in the fridge for longer, and they'd separate out nicely, but I didn't pay attention to how it progressed to that point. I'm hoping to brew tomorrow, so it's got another day to sit.

 

[VikeMan]

Hard to tell from the pic, but it It kind of looks like clumpy proteins/lipids. Does it seem like a semi-solid mass to you, or just hazy? The latter would suggest suspended yeast.

My rules of thumb for crashing starters, depending on strain:

Fast Flocculators (e.g. WLP002): Overnight
Medium Flocculators (e.g. WLP007): 2 days
Slow Flocculators (e.g. WLP001*): 3 days

When planning to cold crash and decant a starter, make sure it's finished before beginning the crash. If not, it may take extra long for the yeast to settle.

*I know White Labs calls WLP001 a "Medium" flocculator. One of the finest examples of advertising puffery.

 

[timsch]

Definitely not semi solid, but somewhat of a very thin gelatinous liquid it appears. Hard to describe, but the hazier region had a whispy quality to it at the top when it mixed with the clearer liquid above it after I tilted the jar back and forth.

It's a WLP820 starter. I had it on the plate for 4 days. THere was still a bit of foam/krausen on the top when I stopped it, figuring it had to be done after 4 days @ 80F, stirring the whole time. This 4 days was actually the 2nd stage step up from a 2c starter I made from a sample stored in glycerine mix in the freezer, so it had plenty of yeast to start at the beginning of the 4 days. You can see the krausen over flow residue from the 1st day.

 

[wepeeler]

You'll be tossing a lot of yeast if you decant, but the stuff that's settled is perfectly fine to pitch, especially after 4 days in the fridge. I'd rather pitch mostly yeast vs spent dme. I rarely pitch the entire starter.

 

[timsch]

Definitely not pitching all that spent DME. I'd hate tossing good yeast, but if it were only 10%, I'd do it. I have no idea about that, though.

 

[day_trippr]

Flogging yeast for four days on a stir plate seems abusive...

 

[wepeeler]

Flogging yeast for four days on a stir plate seems abusive...

True. I contacted Omega, and they say 24 hours is plenty of time.

 

[day_trippr]

Indeed.

Aside from my resurrecting the Trappist "Family Yeast" strain used by our now retired Spencer Abbey Brewery from dregs I'm pretty sure I've never spun a starter longer than 24 hours - and I often do 5 liter starters...

Cheers!

 

[wepeeler]

Indeed.

Aside from my resurrecting the Trappist "Family Yeast" strain used by our now retired Spencer Abbey Brewery from dregs I'm pretty sure I've never spun a starter longer than 24 hours - and I often do 5 liter starters...

Cheers!

Edited for clarity - They also said a 1:10 ratio was what they do. 100ml of healthy yeast solution into a 1L starter. Contrary to many yeast calculators.

 

[timsch]

So, does this damage the yeast? Would there be a difference in beer quality using a flogged starter?

I've generally based the time off of when the foam/krausen on top reduces, thinking that if it's still there, it's still active.

What are the ramifications of a greater ratio? I made my 1st step using a 30ml vial with 2c of DME wort.

 

[wepeeler]

So, does this damage the yeast? Would there be a difference in beer quality using a flogged starter?

I've generally based the time off of when the foam/krausen on top reduces, thinking that if it's still there, it's still active.

What are the ramifications of a greater ratio? I made my 1st step using a 30ml vial with 2c of DME wort.

It doesn't damage the yeast. Just saying you can use less than you think to make a starter. A 1:10 ratio is not what most online calculators will say. 24-48 hours is plenty of time for the starter to finish. Greater ratio means you're using more yeast than you need to.

 

[VikeMan]

They also said a 1:10 ratio was what they do. 100ml of healthy yeast into a 1L starter. Contrary to many yeast calculators.

You probably know this, but their wording is awkward and potentially misleading. I'm sure they meant 100ml of previous starter (i.e. the resulting yeast and "beer") into 1L of starter wort. Not 100ml of dense yeast, which would be a way too big an inoculation for a liter of wort.

 

[wepeeler]

You probably know this, but their wording is awkward and potentially misleading. I'm sure they meant 100ml of previous starter (i.e. the resulting yeast and "beer") into 1L of starter wort. Not 100ml of dense yeast, which would be a way too big an inoculation for a liter of wort.

Correct. 100ml from either previous starter or harvested yeast solution into 1000ml of fresh medium.

 

[VikeMan]

Correct. 100ml from either previous starter or harvested yeast solution into 1000ml of fresh medium.

I would add that "1:10" is sort of a British tradition rule of thumb. In American breweries, I think 1:8 is probably more common. And the Germans favor 1:4 (which happens, not coincidentally, to approximate some step-up calculator recommendations).

Theoretically, with enough nutrients, you could go "1:ReallyBigNumber." But a problem with that is that with very low inoculation rates, yeast seem to start having problems with using complex sugars.