Question about yeast starter temp

I've heard that you can make a starter to grow the yeast and then let it floc out in the fridge, decant the spent wort, and then pitch it which is better if you are making a very large starter and don't want the spent starter wort in your beer. I've also heard that it's best to pitch the yeast at the height of its activity which would require that you not let it cool down and floc out and decant the spent wort. My question is actually for the second method and the effect that cooling has on yeast activity. I'm planning to ferment a beer at 66, but my room temp is 74. So my starter will be active and ready to go at 74 degrees. It seems to me that cooling the starter to pitch at 66 would reduce the yeast's activity and take away some of the advantage of the active starter as opposed to the cooled/floc'd/decanted starter. Even chilling the wort to just 72 and pitching the active starter would still require cooling the beer in the fermenter down to 66 which seem like it would have a negative impact on yeast activity. Am I over-thinking this or are these real concerns? If I cool the starter at height of activity is the effect negligible as long as it's gradual?

To some extent, you're making it overly complicated. There's plenty of evidence that the recc to pitch at the height of activity is too early....the yeast has stored more glycogen and is healthier if you let it go beyond that time point. Just let it ferment out, cool and decant the spent wort....just don't let it sit around for several days or anything. I find that making a starter 48-60 hours ahead of brew time is about right for my system. Just after it's done fermenting, I put the starter in the fridge for 10-12 hours to drop any suspended yeast out and pull it out and decant. If it's still fermenting when you cool the starter, it won't clear as well.

Pitching it into 66 degree wort will not cause problems and the beer will ferment well if you made an adequate starter, although the yeast growth phase will probably be more productive at a slightly higher temp (depending on strain, etc).

Belmont pmmed me for imput...and I really don't have any. Well, sort of

Just my experience, which is limited because I se dry for 90% of my beers though whenever I use liquid I do make a starter for it, and I also bottle harvest and yeast wash yeast too.

I never bother cold crashing my starters, if you make them far enough in advance they will flocculate out and you can decant, and probably the amount of leftover yeast dropped out by cold crashing a clear starter is probably negilgable (and I kinda think any yeast that you have to cold crash out is probably not the healthiest of most active of the colony, everyone else has done the job and taken a rest.....so these are probably the "idiot cousins" of the rest of the yeast and if they take a long time to work in your starter, they're going to do the same thing in the primary..

SO I really don't know.

The only time I did cold crash one, I let it warm back up to room temp by pitching time, because, in my way of thinking, pitching cold yeast into a warm fermenter will either result in thermal shock for the lil critters, or at least cause there to be a longer lag time, because you have forced the yeast into dormancy, and now they have to wake back up and reproduce.

I am also one of those who believe (whether or not it is true) that pitching at "high krausen" is actually a great thing to do....My only experience of being lucky enough to have a flask of starter still at krausen by pitching time, resulted in a gangbuster fermentation and the only time, IIRC that I needed to use a blowoff tube.

Honestly, I think this is one of those "apples and oranges" kinda thing, like so much of homebrewing...the two ways you posited are both ways to skin a cat, and will both work effectively...it's just a matter of what works better in your personal brewing process.

This is the first I've heard of pitching at high krausen being a bad thing. I have heard the glycogen reserves argument but thought that was more to maintain yeast cell viability for storage. I've also heard Palmer say that if you let it go beyond a certain point that they start to weaken by using up those glycogen reserves. He said that 36 hours is pretty much the maximum time before that begins to happen. I'm sure results would vary depending on the gravity, aeration, original yeast viability, etc.

The only thing that pitching at high kreausen of concern is the "possible" off-flavors in the starter wort, however, a 1-2 liter starter in 5 gal (19L) of wort would have a negligeable impact on flavor, and with an extended primary the yeast would clean up some of the off-flavors, if any were to occur anyhow.

Chilling an decanting allows only the yeast slurry to be pitched rather than the entire starter, and chilling also allows the yeast to replenish their glycogen reserves while going dormant. This translates into a yeast that has more energy stored for reproduction.

There are pros and cons to both, personally I try to pitch at high krauesen when the yeast is in munchie mode, but if life happens and brew day gets delayed I toss it in the fridge for a couple days and decant the starter wort, allow it to warm to room temp when I start to brew and its ready to be pitched by the time I'm done.

A 10° temperature swing is acceptable when pitching, more than that can cause yeast shock lengthening lag times. Pitching as close to fermentation temperature possible is ideal.

I often make the starter, let it ferment out, then put it in a water bath (with a little ice when required) and slowly drop the temp from room temp to 65-ish. As mentioned above, it will flocc out sufficiently at that temp. Then I decant and pitch the thick slurry.

Within our normal beer fermentation temps, pitching cool yeast into warmer wort is better than pitching warm yeast into cooler wort. The yeast can withstand a larger temp difference when going from cooler to warmer (to a point of course).

Then there is the concern with getting better growth rates at higher temperatures.

Ok guys. Last night I made a starter and was thinking of trying something new to me. I put the starter in my fermentation fridge and set it to the temp I intended to ferment at(66F). I check on it this morning and the yeast looked to be all flocculated out already. With that short amount of time I'm guessing that I didn't get the growth that I wanted. I was hoping to pitch at high krausen today but if the yeast is already flocc'd out then I'm guessing this starter is going to be far from ideal. What are my options here? Should I go buy another package of yeast and start over and brew tomorrow instead?

Are you sure the starter even started fermenting? Can you see a krausen ring clinging to the sides of the starter vessel? It may have not even started yet...I'd be a little surprised if it started and finished completely overnight...especially at that temp.

If you're not sure and it doesn't really look like you had a fermentation in there...then I would wait and see if it starts. I would rouse it up too, more than once if needed. You could take a hydro sample and see what the gravity is...just be sure to be uber-sanitary (however if it doesn't look like you had a fermentation yet then I would just be patient and not muck around in it).

Many sources say that even for lagers you should grow the starter at room temp.

IMO, if it hasn't started yet then you prob should push back the brew date until it has.

EDIT: FWIW, I made a starter on Wed night using a slurry of washed Pacman yeast and it didn't take off fast enough so I'll prob have to push Saturday's brew to Sunday. That's why I always shoot for Saturday...gives an extra day 'fudge-factor'.

I'm seeing CO2 bubbles now that I've taken it out of the fridge. I'm shaking it intermittently and something is going on. The fact that I can see yeast at the bottom is what concerns me. I may take a gravity reading. I just don't see how that yeast could have done it's work in 10 hours at 66F.

Growing starters at higher temps will make more yeast quicker, but the yeast will not be as healthy in comparison to a starter that is grown @ approx 70-72° (which is the median optimal growth temperature).

Did you allow the starter to sit out for an hour or two at room temp (~70-75°) before placing it in your ferm chamber @ 66°?

If so, what yeast are you using and what is its optimal ferm temp?

Using a stirplate under the cooler temperatures in your ferm chamber would have a positive impact as well.

I agree 10 hours at such a low temp (66°) would be unlikely that the sarter would be ready.

My starters at between 72-75° take at least 15 hours or so to begin showing a kreausen, and that is on a stir plate!

FWIW, good experiment.

I wouldn't worry about the yeast at the bottom...once the fermentation really kicks in it should cause enough churning action to rouse it...plus you're rousing it yourself. Give it a little time.

If you can tell it's starting to ferment then I wouldn't take a gravity reading. But I'm the type that just doesn't muck around in my beer (and ESPECIALLY a yeast starter) unless I really, really need to. I never even take hydro samples out of my beer...I catch a sample when racking it and that's it.

It's showing 2 degrees above room temp now so I'm pretty sure its fermenting. I'll move brew day back to tomorrow because I'm pretty sure its going to be a while before this thing really takes off.

I'm using the Wyeast 1968 London ESB by the way. Recommended temp range is 64-72. I'm in Texas and it is hot. Room temp is 74 and I keep my house cooler than a lot of people here in the summers. I'm worried about the high temp. Should I set the fermentation fridge to 68 and put it in there? I'm worried that dropping the temperature may make the yeast lazy.

74 F is fine for a yeast starter...about ideal.

That's room temp. The thermo-strip is reading 76.