How long on stir plate?

[whovous]

Is it OK to leave a starter on a stir plate for almost three days? I have to leave town for a while, and want to brew about a day after I get back. I've just made a 1L starter with Propper Starter and a fair amount of Hansens Ale Yeast that I took from a two step starter about six weeks ago. I plan to split the result in two and save the other half.

Is this too long to leave it at cool room temp (65-68F)?

 

[IslandLizard]

I think it will be A-OK.
I often spin my starters for 3-5 days. Always for an additional 12-24 hours after the color changed to a significantly lighter shade. Sometimes it takes over a week, such as with the last YeastVault vial I got in March.

Now a 1 liter starter of 1.040 wort is a bit small already, and you're only going to use half of that?
Did you use a yeast calculator?

 

[whovous]

The key point is that there was a ton of yeast from the batch six weeks ago. If it is alive, I have more than enough, based on my highly scientific sight test. I guess this is more of a vitality starter, or just my way of convincing myself that the prior batch did not die on me in the fridge. It didn't. An hour or two after I pitched, I already had a decent visible krausen.

In the past, I brewed far too infrequently and just bought new yeast each time. Now, I am very enamored of the Hansen Ale Yeast I got from one of those White Labs vault things. I cannot buy it again, so I am trying to make sure I always have more available.

 

[IslandLizard]

The key point is that there was a ton of yeast from the batch six weeks ago. If it is alive, I have more than enough, based on my highly scientific sight test. I guess this is more of a vitality starter, or just my way of convincing myself that the prior batch did not die on me in the fridge. It didn't. An hour or two after I pitched, I already had a decent visible krausen.

In the past, I brewed far too infrequently and just bought new yeast each time. Now, I am very enamored of the Hansen Ale Yeast I got from one of those White Labs vault things. I cannot buy it again, so I am trying to make sure I always have more available.

Sorry, I misunderstood. Most vitality starters are pitched entirely. I guess you can save some out if you started with a large cell count already.

I always make them too. I've had bubbling within 4 hours. I oxygenate the vitality starter, let it stand for an hour under the foam, then put on the stir plate (or shaker).

On a side note, if you're interested in buying grain, our Group Grain Buy is closing sometime tomorrow afternoon.

 

[whovous]

I've thought about the Group Buy on occasion, but I think I still brew less than fifty gallons a year. Combine that with not knowing what I want to do next and I don't think the group buy makes sense for me.

 

[IslandLizard]

I've thought about the Group Buy on occasion, but I think I still brew less than fifty gallons a year. Combine that with not knowing what I want to do next and I don't think the group buy makes sense for me.

I understand.
Aside from a sack of base malt you'd use in most brews, such as e.g., Golden Promise, there's little point. And that still would last you for well over a year.

The buy has slowed down drastically the past few years, fewer participants, smaller orders.

 

[IslandLizard]

Back on topic, I've rarely (uh, never) gotten enough growth in 24 hours from a "fresh" pack on a stir plate or shaker, even when oxygenated right before.

Maybe I don't know what to expect, but the color changing from brown or dark tan to light tan or creamy is my clue (unless it's WLP002/WY1968, which turn into "egg drop soup" when done), and it never happens in that short time period.
Instead, it takes 2-3 days from most fresh packs. I give it the extra 12-24 hours after the color change, for all security. I usually end up with a big yeast cake, about 1/2" in a 1/2 gallon pickle jar or 2 liter flask, about 4 ounces of thick, barely pourable slurry. Occasionally more.

Now most "fresh" WLP or WY I get here (MDHB) is 2-3 months old, but with WhiteLabs' PurePitch packs that should not be a problem, with only 3% viability decrease per month, at least during the first 3-6 months.

Look closely at inoculation rate/starter volume vs. growth on BrewUnited's yeast calc. and see how changing those helps in maximizing growth.

Even with only 50 billion (viable) cells at the onstart (half the settled slurry level in an old WLP yeast tube) you can easily get 300 billion cells in a 1.8 liter starter, when done. But, I doubt that happening within a mere 24 hours, unless that slurry is already active, ready to go, freshly harvested from a previous starter, not cold crashed.
Such as using 200 ml of the previous starter, without crashing and decanting, and adding 1.8 liter of fresh 1.041 wort (yielding effectively 2 liters of 1.037). Something like that.

Over-stirring, past done is not recommended. So letting half of your fresh active vitality starter stir another 3 days with fresh wort may be too long. With a crashed slurry that's no more than a few weeks old, probably perfect.

I need to re-read the yeast book again.

 

[Unicorn_Platypus]

I find that 24 hours is usually perfect. Sometimes I'll go longer if I pitched cool or it was a slow start (48 hours at the very most, but that is rare).

You can visually tell when the yeast is done replicating...at that point stick the sucker in the fridge

Most of the yeast I get is pretty fresh though. And I usually pitch two packs in 3.5-5 Liter starter for 10 gallon batches. I always chill and decant. Prefer not to dump that oxidized wort in my fermentor especially if its a big starter

Might take longer to start for smaller starters with less yeast. I don't have experience there, so longer might be better. When its milky and yeasty its done.

Here's the dude from Wyeast. I would listen to him. He says 18-24 hours

 

[day_trippr]

So this is the same yeast that's going to chew through five gallons of wort in 4-5 days that's likely verging on twice the original gravity - and you think it takes 3+ days to go through a couple of liters on a stir plate?

fwiw, I typically run stirred starters for 18-20 hours, usually around 70°F. Rarely longer - even my 5 liter starters. We're not really going for terminal gravity, we're just going for replication, which ends before the wort is totally spent.

As for the OP's situation: the wort will be even more horribly oxidized after 3 days on a 'plate, so I would definitely want to crash that starter before warming what's left back up before pitching...

Cheers!

 

[Day-Day]

For what it's worth, I aim to make make my starters 24 hours before I plan to pitch them... I often pitch my starter 18 hours after they are made. I've left them on the plate for up to 72 hours. I've crashed the starter and pitched just the slurry. My preferred method is make my starter the day before I brew and pitch the whole starter at high krausen.

If it were me, I would have left the starter on the stirplate for 24-48 hours, then back in the fridge while I was out of town. Then brought it up to room temp before I pitched.

You'll be fine either way.