cold crashing yeast starter VS NOT

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basilchef

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Ive got a simple 1200ml yeast starter (1056) going on a stir plate. I placed it on the stir plate at 4 pm yesterday. (its been 20.5 hrs). i plan on brewing tomorrow I have a few questions concerning the process after i take it off the stir plate. First, is it better to let the yeast stay at fermentation temp for the duration of a total of 42 hours or is it best to cold crash after 24? The yeast on my stir plate is still cloudy. Also, what are the results of leaving the yeast on the stir plate for the duration? lastly should there be a "rest" (off the stir plate but before the frige) of the yeast before crashing? thanks for all responses. -cheers
 
1) Depends on how much starter beer you're ok with going into your wort. It doesn't taste particularly good, so it can be a concern, but I am of the opinion that the size of a starter relative to the size of the batch makes negligible.

2) I brewed a beer on Friday that I had left the starter on the stir plate for ~54 hours before pitching right into the wort. I got an insanely active fermentation on the 1.070 wort which actually resulted in my first blow out since I started brewing. Shifted over to a blow off tube and all was well.

3) If you're going to crash, you don't need to wait. Just throw it in the fridge and pull it out when you start brewing. That way it will be up to pitching temp when you're ready.
 
1) Depends on how much starter beer you're ok with going into your wort. It doesn't taste particularly good, so it can be a concern, but I am of the opinion that the size of a starter relative to the size of the batch makes negligible.

2) I brewed a beer on Friday that I had left the starter on the stir plate for ~54 hours before pitching right into the wort. I got an insanely active fermentation on the 1.070 wort which actually resulted in my first blow out since I started brewing. Shifted over to a blow off tube and all was well.

3) If you're going to crash, you don't need to wait. Just throw it in the fridge and pull it out when you start brewing. That way it will be up to pitching temp when you're ready.

thanks for the reply. i unfortunately had to make the decision before i left to work this afternoon. results: i pulled the yeast off the stir plate after 21 hours. placed directly into the fridge and when i got home a few minutes ago i checked my yeast. what i found was a flask with almost a quarter inch of yeast and sediment on the bottom and a nicely flocculated beer on top. looks to be a nice product. i would still like to know everybody's view on this subject. i hear a lot of mixed reviews on the best way. i have tried several different ways but always end up with delicious and intoxicating beer. i just was wondering if there was a "right" way to do it. thanks again and cheers
 
This is one of those areas of brewing where there's no right or wrong way. Many options:

1. Cold crash the yeast, pull from fridge and pitch just the yeast at 35-40F after pouring off the beer.
2. Cold crash the yeast, pull from fridge, let it warm to wort temp, then pitch after decanting.
3. Let the yeast settle at room temp, then pitch the entire starter.
4. Let the yeast settle at room temp, then pitch just the slurry.
5. Pitch entire starter directly from stir plate.

All of these work, and people practice every option. Generally, people will say that 3 is better than 4, but I'm not sure if anyone knows exactly what the difference is, in number of yeast cells.
 
This is one of those areas of brewing where there's no right or wrong way. Many options:

1. Cold crash the yeast, pull from fridge and pitch just the yeast at 35-40F after pouring off the beer.
2. Cold crash the yeast, pull from fridge, let it warm to wort temp, then pitch after decanting.
3. Let the yeast settle at room temp, then pitch the entire starter.
4. Let the yeast settle at room temp, then pitch just the slurry.
5. Pitch entire starter directly from stir plate.

All of these work, and people practice every option. Generally, people will say that 3 is better than 4, but I'm not sure if anyone knows exactly what the difference is, in number of yeast cells.


Not sure why 3 would be any different than 5.

To the OP, the advantage of cold crashing is it gets rid of nasty spent starter wort. There is no right or wrong way, but if you have the time, I think cold crashing is worth it.

Best to decant while it is still cold so it takes less time to warm up. Then let the yeast layer warm to fermenting temp before pitching. You do NOT want to pitch the yeast while still cold as the warmer wort will shock them.
 
I have only made one starter so far. What i did was smack the pack before i went to bed. In the morning (7 am) i made my starter wort cooled it to room temp and pitched my yeast in. I let that ferment until around 5 pm the next day when i pitched it to my room temp batch and then chilled it down in n swamp cooler. by 5 pm the next day i had a solid fermentation going on a 60 degree wort
 
Pablo has it right. No difference in 3 or 5, except it takes longer to wait for the yeast to settle. Makes no difference if you pitch the whole thing anyway.
You always want the yeast at the same temperature as the wort. You also need to keep in mind that the starter wort probably is not very tasty, so pitching only the yeast is a good idea.
Cold crashing causes the yeast to go dormant and settle, so this helps you separate out what you don't want.
 
How long can you keep the "crashed" starter in the fridge before needing to pitch it?
 
How long can you keep the "crashed" starter in the fridge before needing to pitch it?

Best way to tell is just look at the viability on a site like Mr Malty. You can go a week or so with little change in viability.
 
Pablo has it right. No difference in 3 or 5, except it takes longer to wait for the yeast to settle. Makes no difference if you pitch the whole thing anyway.
You always want the yeast at the same temperature as the wort. You also need to keep in mind that the starter wort probably is not very tasty, so pitching only the yeast is a good idea.
Cold crashing causes the yeast to go dormant and settle, so this helps you separate out what you don't want.

Old post bump...

FWIW, it can be argued that cold crashing allows the yeast to rebuild glycogen reserves thereby providing stores for healthy aerobic reproduction phase.
 
Old post bump...

FWIW, it can be argued that cold crashing allows the yeast to rebuild glycogen reserves thereby providing stores for healthy aerobic reproduction phase.

I'm no biochemist, but I have to ask... how? When you cold crash the yeast go dormant, so if they're dormant, how are they building up their glycogen stores? Especially if there's no sugar present from which to build said glycogen stores.
 
If its commonly accepted that you want to have the yeast slurry be the same temp as the beer when you pitch it (ie, letting the start warm up outside the fridge while you brew), then why is it that most dry yeast manufacturers recommends re-hydrating in 85-95F water before pitching? Seems like if you have a temperature difference, it would be better for the yeast to go from cold to warm, as opposed to warm to cold, to avoid them going dormant?
 
I'm no biochemist, but I have to ask... how? When you cold crash the yeast go dormant, so if they're dormant, how are they building up their glycogen stores? Especially if there's no sugar present from which to build said glycogen stores.

It was my understanding that the yeast build up glycogen stores before going dormant when they finish a meal. My guess is that cold crashing interrupts their meal and they go to sleep before building those stores. If they have fully attenuated the starter they have probably prepared for going dormant and are just waiting for gravity to settle them out. It should be alright to cold crash in order to decant the spent wort at this point.
 
If its commonly accepted that you want to have the yeast slurry be the same temp as the beer when you pitch it (ie, letting the start warm up outside the fridge while you brew), then why is it that most dry yeast manufacturers recommends re-hydrating in 85-95F water before pitching? Seems like if you have a temperature difference, it would be better for the yeast to go from cold to warm, as opposed to warm to cold, to avoid them going dormant?

Rehydration is the process of waking them up, and it doesn't stay warm for long. Bakers and brewers both use the same range of rehydrating water. Just warm your yeast up gradually and pitch when it is the same temp as the wort.
 
ghpeel said:
If its commonly accepted that you want to have the yeast slurry be the same temp as the beer when you pitch it (ie, letting the start warm up outside the fridge while you brew)...

Got sources? I've never read that you need to let yeast warm up slowly (and what would be "slowly"?) before pitching. Even if I did read it, I'm not sure I'd believe it since I've never had problems pitching straight from the fridge. You could be right; I simply don't know.
 
If you are not planning on pitching the yeast right away, you can store it in the refrigerator with the foil still in place.

When you are ready to brew, decant off most (80%) of the clear liquid from the top, being careful not to disturb the yeast layer below. Once the yeast and your wort are at approximately the same temperature, rouse the starter yeast into suspension with the remaining malt solution and pitch the yeast slurry into your wort.


White Labs Web Site
 
The best way to pitch a starter is at high krausen without cold crashing, which means that a brewer who wishes to pitch a starter at the peak of its health needs to accommodate the starter media. Temperature fluctuations affect yeast metabolism and waiting until a starter ferments out leaves a culture in the stationary phase, which is the point where sterol and unsaturated fatty acid stores are lowest.
 
The best way to pitch a starter is at high krausen without cold crashing, which means that a brewer who wishes to pitch a starter at the peak of its health needs to accommodate the starter media. Temperature fluctuations affect yeast metabolism and waiting until a starter ferments out leaves a culture in the stationary phase, which is the point where sterol and unsaturated fatty acid stores are lowest.

That only really makes sense for smaller starters, or if you decant and then add a small amount of wort to be able to pitch at high krausen.
 
This article has a contrary opinion, that it is just fine to pitch cold yeast into warmer wort, but no vice-versa: http://morebeer.com/brewingtechniques/library/backissues/issue4.2/miller.html

The Siebel Institute is a pretty good source.

Old thread bump. This article seems to contradict everything I've ever read or done in practice. Typical for a yeast conversation I guess.

Most strangely, though: The warning about "cool shock" seems to fly in the face of the entire practice of cold crashing. I regularly cold crash my yeast starters and always my beers, sometimes even harvesting after a cold crash without issue. He's suggesting a drop in temp of 18F would be "serious" and kill a yeast population, which can't be true on a significant level.

He's also advocating an very weird practice here imo:

If your starter is more than 18°F (10°C) warmer than your intended fermentation temperature, I suggest pitching at a warmer temperature to avoid cold-shocking the yeast. Then ramp the temperature down over the next couple of days. Based on my experience, a ramp or 3-4°F per day works well.

This is kind of crazy, right? First off, why not just cool down the starter if this is a concern (which again, seems flimsy anyway)? Second, a great way to ruin a lager (or any beer really) is to ferment the first 3-4 days at 5-15F over your desired temp.
 
When I have time to crash a starter the morning of a brew day I'll decant most of the liquid, then set the flask back on the stirplate and let it spin on low while I brew. this puts all the yeast nicely back into suspension and allows it to warm up to room / pitching temp.

Works great for me, I usually see a vigorous fermentation within about 12 hours with a healthy krausen.

When I don't have time to crash I just dump the starter in full stop. also works fine. I've never noticed any real difference between crashed and non-crashed starters but I still prefer to crash as the idea of an extra 1000ml or two of liquid that's not my actual beer isn't as appealing to me.
 
When I have time to crash a starter the morning of a brew day I'll decant most of the liquid, then set the flask back on the stirplate and let it spin on low while I brew. this puts all the yeast nicely back into suspension and allows it to warm up to room / pitching temp.

Works great for me, I usually see a vigorous fermentation within about 12 hours with a healthy krausen.

When I don't have time to crash I just dump the starter in full stop. also works fine. I've never noticed any real difference between crashed and non-crashed starters but I still prefer to crash as the idea of an extra 1000ml or two of liquid that's not my actual beer isn't as appealing to me.

I do the same. I was originally digging around in here because I was worried about an inadequate cold crash, which would mean when decanting, I'd be dumping out the 'finishing' yeast that runs that last mile of fermentation. I've not found a good answer to this. I emailed WL and they told me "24 hours is plenty of time" (I seem to usually be in the 12-48 hour range...sometimes brew day gets delayed because of life, ect).

I guess this is more of an issue if I'm recycling yeast, but I very rarely am doing that although would like to start the oversized starter/harvesting technique soon. The problem is I very rarely am using the same yeast twice in a three month period and am not sure it's worth storing 15 different strands of old yeast.

I also worry that the yeast harvesting technique further clouds any way of determining what my actual cell count is. There are enough variables as in when you're pitching direct from vile to fresh starter.
 
Most strangely, though: The warning about "cool shock" seems to fly in the face of the entire practice of cold crashing. I regularly cold crash my yeast starters and always my beers, sometimes even harvesting after a cold crash without issue. He's suggesting a drop in temp of 18F would be "serious" and kill a yeast population, which can't be true on a significant level.

He's also advocating an very weird practice here imo:

If your starter is more than 18°F (10°C) warmer than your intended fermentation temperature, I suggest pitching at a warmer temperature to avoid cold-shocking the yeast. Then ramp the temperature down over the next couple of days. Based on my experience, a ramp or 3-4°F per day works well.

This is kind of crazy, right? First off, why not just cool down the starter if this is a concern (which again, seems flimsy anyway)? Second, a great way to ruin a lager (or any beer really) is to ferment the first 3-4 days at 5-15F over your desired temp.

I don't think the argument is so flimsy. Cold crashing is about forcing flocculation, not about prepping yeast for active fermentation. Cooling yeast can put them to sleep, making them less active, slowing fermentation. So, when you're cold crashing a starter, when you pitch the yeast you're pitching cold yeast into warmer wort, which yeast will love, and will wake them up. If you pitch warmer yeast into colder wort, you will put them to sleep, which could slow fermentation.

I always cold crash lager starters, I don't want a gallon of starter beer in my actual beer. So, I can't speak to real world on this. But I do think the logic holds.

I also don't love the idea of pitching into a warmer wort, then cooling over a couple of days- but this is not an uncommon practice in lagers, I have seen it as a recommended practice many times. I pitch cold, decanted yeast into fermentation temp beer, and get excellent attenuation and fermentations. So ultimately I can only speak from experience with those parameters.
 
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