Author Topic: Re-pitching technique...  (Read 1625 times)

Offline tomsawyer

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Re: Re-pitching technique...
« Reply #15 on: November 14, 2011, 12:52:32 PM »

I like to rinse the yeast cake upon harvesting to remove any trub or hop particles to mitigate any potential bacterial infection.

That's an interesting thought. Is your concern that the trub might be contaminated (which seems unlikely since it's been boiled), or that it might be a food source for bacteria?

IMO, The latter...I like to keep out any potential competition. If the significant portion of the slurry is yeast and water, there is a lot less potential for bacterial contamination and off flavors.
Why do you think theres any contamination in a trub or hops?  If there were you'd see it growing in the beer.
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Offline miguelpanderland

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Re: Re-pitching technique...
« Reply #16 on: November 14, 2011, 12:57:16 PM »
Wow.  75 ml of slurry is slurry is enough to do the job?
A white labs vial has a "Net Volume" of 35 mls, so you're over twice that.  That is plenty for an average gravity ale.  For stronger wort or a lager you'd want more.

Great info.  Then is the only benefit to pitching right on top of a fresh yeast cake the speed with which the job will get done?
It will get done faster, but you may lose some yeast character.  About the only time I would go right on top of a yeast cake is if I was brewing some kind of massive beer and needed to do a 5 gallon starter.  Also, if your slurry is old you should use more or make a starter.

So then when making the starter, would you use the whole slurry or just the 75 ml slurry?

Offline tschmidlin

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Re: Re-pitching technique...
« Reply #17 on: November 14, 2011, 01:01:13 PM »
So then when making the starter, would you use the whole slurry or just the 75 ml slurry?
It would depend on the wort it was going into and how old the slurry is.  The older it is, the more you'll want to use in the starter.  The stronger the wort is, the more you'll want to use in a starter.  I'd look at the Mr. Malty calculator to get an idea, I don't use it as gospel but it will give you a good idea of how much to use.
Tom Schmidlin

Offline miguelpanderland

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Re: Re-pitching technique...
« Reply #18 on: November 14, 2011, 01:17:48 PM »
So then when making the starter, would you use the whole slurry or just the 75 ml slurry?
It would depend on the wort it was going into and how old the slurry is.  The older it is, the more you'll want to use in the starter.  The stronger the wort is, the more you'll want to use in a starter.  I'd look at the Mr. Malty calculator to get an idea, I don't use it as gospel but it will give you a good idea of how much to use.

Question about making the starter, is it cool to just do as bluesman suggests?  Or do you want to make the starter and let it "build up"?

Offline tschmidlin

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Re: Re-pitching technique...
« Reply #19 on: November 14, 2011, 01:23:18 PM »
So then when making the starter, would you use the whole slurry or just the 75 ml slurry?
It would depend on the wort it was going into and how old the slurry is.  The older it is, the more you'll want to use in the starter.  The stronger the wort is, the more you'll want to use in a starter.  I'd look at the Mr. Malty calculator to get an idea, I don't use it as gospel but it will give you a good idea of how much to use.

Question about making the starter, is it cool to just do as bluesman suggests?  Or do you want to make the starter and let it "build up"?
It's another question of how old the slurry is.  For an older slurry I would make a starter a couple of days ahead of time, cool it and decant.  You can still add some fresh wort a couple of hours before to get the yeast going prior to pitching.
Tom Schmidlin

Offline miguelpanderland

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Re: Re-pitching technique...
« Reply #20 on: November 14, 2011, 01:26:17 PM »
Loads of information in this thread now.  Wow.  Thanks for all the help everyone.  The days of endlessly buying vials of yeast are coming to a close....

Offline davidgzach

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Re: Re-pitching technique...
« Reply #21 on: November 14, 2011, 01:30:47 PM »
I've already got the yeast decanted in the fridge.  When saving yeast from the carboy I used boiled (and then chilled) water before transferring to the storage containers.  Total volume of slurry is probably around 3 cups.  At this point it's been in storage for two weeks.  To "rouse" the slurry with a starter, how big of a starter would you make?

The forum is a huge bonus! 

I looked back and if the slurry is only two weeks old, you are probably good to go without a starter and a cup of slurry direct pitched.  Just warm to pitching temp and bombs away. 
Dave Zach

Offline ynotbrusum

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Re: Re-pitching technique...
« Reply #22 on: November 14, 2011, 07:45:45 PM »
Just warm to pitching temp and bombs away. 

Okay to do, but not necessary if going from 40 or so to pitching temperature (assuming pitching temperature is 60 or so for ales and 45-50ish for lagers)....

I use slurry all the time and try to time my brewing to allow harvesting on the day of brewing, with yeast collected at fermenting temperatures (I don't do a diacetyl rest for this reason, among others).
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Offline corkybstewart

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Re: Re-pitching technique...
« Reply #23 on: November 15, 2011, 08:28:09 AM »
I've already got the yeast decanted in the fridge.  When saving yeast from the carboy I used boiled (and then chilled) water before transferring to the storage containers.  Total volume of slurry is probably around 3 cups.  At this point it's been in storage for two weeks.  To "rouse" the slurry with a starter, how big of a starter would you make?

The forum is a huge bonus! 
Just warm to pitching temp and bombs away. 
Be careful when warming a slurry.  I took a 1 pint mason jar out of the fridge and didn't open it immediately.  5 minutes later(if that long) I heard a strange noise and saw that the lid of the jar had pooched out and the ring was distorted. Another couple of minutes and I would have been picking glass shards out of my face, it was almost bombs away..
Open the lid a little to allow any pressure to bleed off peacefully.
I'd really just rather be brewing in sunny Carlsbad New Mexico

Offline bluesman

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Re: Re-pitching technique...
« Reply #24 on: November 15, 2011, 08:33:36 AM »

I like to rinse the yeast cake upon harvesting to remove any trub or hop particles to mitigate any potential bacterial infection.

That's an interesting thought. Is your concern that the trub might be contaminated (which seems unlikely since it's been boiled), or that it might be a food source for bacteria?

IMO, The latter...I like to keep out any potential competition. If the significant portion of the slurry is yeast and water, there is a lot less potential for bacterial contamination and off flavors.
Why do you think theres any contamination in a trub or hops?  If there were you'd see it growing in the beer.


I'm not saying that there is contamination, but trub is a food source for potential bacterial contamination.
Ron Price

Offline davidgzach

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Re: Re-pitching technique...
« Reply #25 on: November 15, 2011, 08:52:21 AM »
I've already got the yeast decanted in the fridge.  When saving yeast from the carboy I used boiled (and then chilled) water before transferring to the storage containers.  Total volume of slurry is probably around 3 cups.  At this point it's been in storage for two weeks.  To "rouse" the slurry with a starter, how big of a starter would you make?

The forum is a huge bonus! 
Just warm to pitching temp and bombs away. 
Be careful when warming a slurry.  I took a 1 pint mason jar out of the fridge and didn't open it immediately.  5 minutes later(if that long) I heard a strange noise and saw that the lid of the jar had pooched out and the ring was distorted. Another couple of minutes and I would have been picking glass shards out of my face, it was almost bombs away..
Open the lid a little to allow any pressure to bleed off peacefully.

A good point.  I keep my slurry in 1qt Powerade containers.  You need to burp them every week or so and make sure to burp them every hour or so when warming to pitch.  I typically take the slurry out of the fridge on brew day, place on the counter and burp every time I pass.  I warm for ales and just place in the lager fridge at 50F for lagers.
Dave Zach