Mr. Malty pitch rate question

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ChuckinWA

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Hi all,
I'm planning for brew day tomorrow, and I'm going to use some WLP001 I harvested/washed about a month ago and have kept in the fridge (my first attempt at harvesting). On Sunday, I took it out of the fridge, let it rise to room temp, then added about a qt of fresh aerated wart from Saturday's brew day. The yeasties came back to life quickly and started bubbling the airlock in the growler within a couple hours.

How much of this should I pitch? If I use the Mr. Malty calculator and on the third tab "repitching from slurry" input the date I harvested the yeast (about a month), it suggests I need 226 ml of slurry. Since I used a "starter" to bring the yeast back to life though, should I instead use the date of my "starter" (Sunday)? If that's the case, the calculator suggests I only need 86 ml of yeast. Confused..:confused:

Question #2: Should I bother cold crashing the growler first thing in the morning to pour off the "beer" before pitching in the afternoon, or just shake it up and pitch the mixture? The airlock is still bubbling as I type this... Thanks!
 
He's talking about the date you harvested the yeast, not the date that you made your starter. So, if you pitched 226 ml of *slurry* into the starter, then that's what he means.

If the starter is still active I wouldn't force it out of suspension by putting it in the fridge. If you use a stirplate or other means of aerating *during* fermentation, then you might want to get rid of the wort in the starter by chilling it, waiting for the yeast to drop out (8+ hours?), dumping the wort and pitching only slurry. But I don't think it's a good idea to stop the yeasties before they finish the starter. That being said, if you made the starter on Sunday, it's likely to finish up by Tuesday morning. If it's slowed down and quiet, I'd chill it, dump the liquid and pitch only slurry. But, if you didn't use aeration during the fermentation and the base beer for that starter isn't so far off from the beer you're brewing, it's not so important.

Clear as mud?
 
Basically, he's calculating the viability of your slurry based on when you harvested it from your fermenter. Once you harvest it and put it in the fridge, some of the yeast start dying or become too weak to ferment. So, you're viability slowly goes down on that slurry, which means you'd have to pitch more of it in order for the number to be enough. If the slurry is from one week ago, then you'd have to pitch less of it than if it's from four weeks ago because there'd be more viable cells in the fresher slurry.

Make sense?

When you make a starter, you're waking up the living cells and getting them to replicate and get healthy.
 
Thanks for the reply Matt. The way I see it, the calculator only has 2 options:

1. Yeast harvested, refrigerated for a month, warmed to room temperature, and pitched.
2. Yeast harvested 2 days ago, then pitched.

There doesn't seem to be any way to account for building NEW yeast cells by making a starter?

BTW, I don't have a stir plate - just swirl it around a couple times a day when I think about it.
 
ChuckinWA said:
Thanks for the reply Matt. The way I see it, the calculator only has 2 options:

1. Yeast harvested, refrigerated for a month, warmed to room temperature, and pitched.
2. Yeast harvested 2 days ago, then pitched.

There doesn't seem to be any way to account for building NEW yeast cells by making a starter?

BTW, I don't have a stir plate - just swirl it around a couple times a day when I think about it.
Click to expand...

Yeah, he doesn't have starters made from slurry in the calculator. I've had good luck with making starters with around 100 ml of slurry, making a 2L starter. I use a stirplate then dump the liquid after chilling and dropping out the yeast. You can mess with the calculator see how many living cells he says you have in your slurry and kind of guess from there.

Since you're not using a stirplate or really aerating during the starter's fermentation, it's not as important to dump that liquid....IMHO...

I'd likely just use the whole starter myself...
 
ChuckinWA said:
How much of this should I pitch? If I use the Mr. Malty calculator and on the third tab "repitching from slurry" input the date I harvested the yeast (about a month), it suggests I need 226 ml of slurry. Since I used a "starter" to bring the yeast back to life though, should I instead use the date of my "starter" (Sunday)? If that's the case, the calculator suggests I only need 86 ml of yeast. Confused..:confused:
Thanks!
Click to expand...

I've often wondered the exact same thing. I've tried this twice and and have gotten good results once. The first time I pitched 500ml of 3 month old Wyeast Irish Ale without a starter as per Mr. Malty suggested. 36 hours later, nothing. I ended up pitching a pack of us-56 to get the job done. On my second try, using the shaking method I used a 2L starter with 3 week old slurry (about 50 ml) 3 days before brewing. Chilled, decanted. 12 hours before I added 1L of wort to get the boys working again and then pitched every thing in the fermenter. It worked fine. So, as far as I can tell, simply repitching from slurry without a starter does not give much success.

However, I am looking for a better method of operation for this procedure. I'm kind of half guessing all the time. It would be nice to have some more precise calculations regarding different OG, batch size, viabilty and size of starter needed when repitching from slurry.

The "how much should I pitch" from the OP, is a great question especially when talking about building a starter from slurry.

Hope this helps!
 
Bizoune said:
I've often wondered the exact same thing. I've tried this twice and and have gotten good results once. The first time I pitched 500ml of 3 month old Wyeast Irish Ale without a starter as per Mr. Malty suggested. 36 hours later, nothing. I ended up pitching a pack of us-56 to get the job done. On my second try, using the shaking method I used a 2L starter with 3 week old slurry (about 50 ml) 3 days before brewing. Chilled, decanted. 12 hours before I added 1L of wort to get the boys working again and then pitched every thing in the fermenter. It worked fine. So, as far as I can tell, simply repitching from slurry without a starter does not give much success.

However, I am looking for a better method of operation for this procedure. I'm kind of half guessing all the time. It would be nice to have some more precise calculations regarding different OG, batch size, viabilty and size of starter needed when repitching from slurry.

The "how much should I pitch" from the OP, is a great question especially when talking about building a starter from slurry.

Hope this helps!
Click to expand...

I've been pretty consistently using about 100ml to make a 2 L starter, decanting and pitching only the slurry from the starter with great results. Works every time for me. I have not pitched just slurry without a starter though.
 
Well, my Tuesday brew day was delayed. The plan now is to brew on Fri the 1st (ease the hangover by drinking homebrew, ha ha). I'm sure my starter will be done with it's major activity by then, so I plan to cold crash tomorrow night, then decant and pitch on Fri afternoon. I plan a double brew day (using extract), so hopefully I'll have enough slurry for 10 gal. I'll let you know how it turns out. Thanks again...
 

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