Cold-crashing yeast starter

[Woodland]

I made a 1L batch of starter yesterday with recycled WL Irish ale yeast. I currently have it spinning away on the stir plate as I plan on making a batch of Irish stout within the week. My question is, is there any point on cold-crashing the yeast if I plan on pitching the entire starter? I'm guessing the starter would be more active if I kept it at room temperature for the next 5-7 days.

 

[chickypad]

It you let it go that long it's most likely going to be fermented out. Most people pitch the whole starter at high krausen, which you are going to miss. IMO you might as well let it settle out and just pitch the yeast slurry.

 

[NordeastBrewer77]

i let all my starters ferment out, cold crash for a day or two, decant and pitch just the slurry. i've done the 'whole starter at high krausen' thing, but i like the results of pitching just the slurry better.

 

[Woodland]

Thanks for the input. This is only my second time using the stir plate and I'm still guessing as to how long high krausen will take, probably 2-3 days. If there's a good layer of krausen by Tuesday I may brew then, but if I can't get to it I may crash it and brew next weekend.

 

[chickypad]

It's probably sooner than that. Depending on the size of the starter and how fast I have the vortex going I find that I usually don't see the krausen. I guess maybe I stir them pretty fast. I didn't really realize the difference until the stir bar got thrown one night and I had a massive blow over. I usually ferment them out also, but if pitching the whole thing I do about 12-18 hrs.

 

[NordeastBrewer77]

It's probably sooner than that. Depending on the size of the starter and how fast I have the vortex going I find that I usually don't see the krausen. I guess maybe I stir them pretty fast. I didn't really realize the difference until the stir bar got thrown one night and I had a massive blow over. I usually ferment them out also, but if pitching the whole thing I do about 12-18 hrs.

i agree that it'll be faster than a few days. i don't use a stir plate, just shake and swirl whenever i think of it, maybe once an hour or so, and my starters are completely fermented out within 48 hours, maybe 72 with a slower starter.

 

[Woodland]

That's something else I was wondering about. If the stir bar whips the krausen back into the starter, it can be hard to tell when you've peaked. There was little bit of foam around the edges from the star-san residue, and it doesn't look any different 22 hours later. If I slow the bar down it may foam up. My last starter had a bit more krausen in it, maybe I ran it at a slower speed.

 

[Sheldon]

is there a special designated speed to run the stir plate? I usually run it as high as it goes for 24 hours then cold crash over nite, decant and pitch. Is this the proper process?

 

[Woodland]

I run it just fast enough so the stir bar doesn't clatter around in the flask.

Here's another thought I had. If you don't get any krausening on a stir plate, how do you know if recycled yeast is viable? I shut down the stir plate to see if anything builds up, if there's a good quantity of yeast in the bottom, or if there's any detectable odor in the flask. Thoughts?

 

[NordeastBrewer77]

when the yeast settles, you'll get a nice layer at the bottom of the flask. just let it run til you know it's done fermenting and then stop the stir bar, you'll have yeast, and it'll settle out then.

 

[Hermit]

I run it just fast enough so the stir bar doesn't clatter around in the flask.

Here's another thought I had. If you don't get any krausening on a stir plate, how do you know if recycled yeast is viable? I shut down the stir plate to see if anything builds up, if there's a good quantity of yeast in the bottom, or if there's any detectable odor in the flask. Thoughts?

I've only done one starter but I could see the solution get thicker.

 

[BBL_Brewer]

Judging a stir plate starter by krausen alone is hard to do. There are other indicators of activity such as color change and smell that will clue you in better. I've also noticed that there is condensation in my jugs when the starter takes off from the exothermic activity of the yeast. Just watch them closely and smell them periodically. When the color starts to change and they smell yeasty instead of malty then you know it's all good. How I tell when my starters are done is by looking at the liquid. It seems that when they are done the yeast try to settle out but can't becasue of the stir plate action. I always see wavy lines in the liquid when mine are done and I attribute that to yeast going dormant and trying to settle out. As far as timeframe gooes, if you start with healty yeast, the starter is normally done within 12-18 hours. 24 tops. But, different strains take different amounts of time and it also depends on how large your starter is and what the ambient temperature is.

 

[chickypad]

I see the starter get very cloudy compared to when I pitched it so I know it's going. But yeah if i was ever worried I'd just shut it off and see.

 

[Woodland]

There's definitely a clouding up of the starter, plus condensation in the flask, there's also a separation of the layers when I shut down the stur plate. I shut it down 2 hours ago, I'll check it this evening.

 

[Woodland]

In the photo you can see where I'm at after about 30 hours. I shut the stir plate off after 24 hours. There's definitely a slurry settling along the bottom and a wee bit of krausen on the top. I'm guessing I'm past high krausen. Maybe I'll let it sit overnight then cold crash tomorrow. Looks like Tuesday is time to brew my Irish stout for St. Pat's. C'mon spring!

 

[user 4295]

With a small starter if you blink you may miss the action. Mine are always fermented out completely after about 24 hours, but I still leave it on the stir plate for a full 72 hours. Then it's cold crashed until brew day. On brew day I decant of the spent wort, leaving just enough to swirl the yeast back into solution, and then pitch it cold.

 

[kh54s10]

I've pitched at both high krausen and after letting the yeast settle and decanting. I have seen no real difference.

On a bigger starter, I decant mostly to keep the volume down.

If you let the starter settle you can see how much yeast is there.

I did one stepped up from just 10 ml of frozen. The first was 500ml and had less that 1/8" settled in a qt size mason jar. The second 500ml and almost 1/4" then a 1500ml in my flask and over 1/4" with twice the area on the bottom of the container.

 

[user 4295]

I've pitched at both high krausen and after letting the yeast settle and decanting. I have seen no real difference.

The only reason I do it this way, besides not wanting to dump a large starter volume in to my wort, is that it can be difficult to plan a brew day around a starter's high krausen.

 

[Bhamsteelerfan]

Okay, one last thing I need help with. I created the starter at 2 pm yesterday. I shut off the stir plate at 11 pm and just now have it back up and running. My brew day is planned for Sunday morning-early afternoon. I want a good strong starter (I'm judging by the activity I'm well on my way). When should I shut down the stir pate and get it in the fridge to cold crash so I can decant it and pitch it Sunday?

 

[BBL_Brewer]

Okay, one last thing I need help with. I created the starter at 2 pm yesterday. I shut off the stir plate at 11 pm and just now have it back up and running. My brew day is planned for Sunday morning-early afternoon. I want a good strong starter (I'm judging by the activity I'm well on my way). When should I shut down the stir pate and get it in the fridge to cold crash so I can decant it and pitch it Sunday?

Well, if you're only doing one step for this starter you started it plenty early. Which isn't a bad thing, it's better than cutting things too close. I usually allow 24 hours to ferment the starter and 24 hours to cold crash (or to just settle the yeast at room temp if it's a high floc strain). Why did you shut off the stir plate over night? You should leave it running throughout the process. Let it finish out (should be done by tonight, tomorrow morning at the latest) and then throw it in the fridge. Take it out on brew day a couple hours ahead of time and let it warm up to room temp before you decant and pitch. Should be good to go.