Author Topic: CJ's Cold Pitching Theory  (Read 7291 times)

Offline BeerSmith

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CJ's Cold Pitching Theory
« on: November 09, 2003, 10:42:31 AM »
CJ,
 I've seen portions of the discussion about your "cold pitching" theory.

 The general idea as I understand it is to take your yeast right out of the refrigerator and pitch it into the cooled wort.  Many report a very fast and vigorous start!

 CJ - since I know you hang out here could you please comment on why/how you think this works?  I'm thinking about trying it on my next batch.

Cheers!
Brad
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cj_in_j

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Re: CJ's Cold Pitching Theory
« Reply #1 on: November 10, 2003, 01:07:58 AM »
Brad -- Sorry, I saw this earlier, but today's been a busy day and I didn't want to just whip out a quick answer that raises more questions than it answers. But, it's almost 10 pm now, and I'm still busy, so it looks like a quick answer is all that's going to happen today or tomorrow.

Cold pitching of yeast works best with harvested yeast. After transferring beer from primary, either leave a pint or so of beer behind or have some pre-boiled cool distilled water to add to the yeast. Swirl to get the yeast in suspension, pour it into a glass container (I use erlenmeyer flasks, but any glass jar is fine), cover the top with sanitized aluminum foil, and put it into the fridge. Make sure it doesn't freeze. Ideally you should brew the next day, but definitely within three days. Keep the harvested yeast in the fridge until you're ready to pitch it into your new wort. Again ideally, the wort should be 5-10F lower than your target fermentation temperature. Pour off the liquid on top of the yeast, leaving just enough behind to liquify the yeast. Swirl and pitch 250 ml (1 cup) to 400 ml (about 1.5 cups) into the new wort, depending on the original gravity. Aerate as well as you can, swirl to mix the yeast into the wort, seal the fermenter, and stand back! In most cases, fermentation will start within 2-4 hours, with vigorous fermentation starting within 6 hours.

Notice there are a few "ideally" statements above. However, until just recently, I used an immersion chiller and couldn't get my wort chilled to under fermentation temps. I've used the cold pitching technique in beers as warm as 78F, which I then continued to cool down with ice bottles strapped to the fermenter. Even with this continued cooling, I had lag times of only 2-4 hours. Second, I said ideally it should be used with harvested yeast. However, I usually make large starters -- at least 2 liters -- and I follow the same basic procedure. Once the starter if fermented out, I put it in the fridge and pitch the same way the next day. Lag time is generally an hour or two longer, but everything else proceeds as usual.

Benefits of cold pitching -- quick starts (2-4 horus), vigorous fermentation (I generally need a blowoff), quick end of primary (3-4 days with most low to medium OG beers), complete fermentation (near or above the high-end of attenuation figures for a given yeast), and healthier yeast for harvesting (I've gone up to 5 generations with the same yeast and probably could have gone quite a few more).

Sorry, I've gotta run -- let me know what questions you have!

Offline cmbrougham

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Re: CJ's Cold Pitching Theory
« Reply #2 on: November 10, 2003, 01:37:12 AM »
cj--

I've been subscribing to the cold pitching practice for my last 8 or 9 batches, and have had good success with it, IMO. I usually end up harvesting 2 cups of slurry from my fermenter--I use quart mason jars, and they're usually about half full. Once the yeast settles out, it's probably about 1.25-1.5 cups of solid yeast. Is this too much to pitch? I see you say to use about 1 cup of slurry... am I overpitching? I've never seen quite as fast a start as you describe--2 to 4 hours--but things are usually moving with 8-12 hours.

Another thing: I see you recommend using the harvested yeast within a couple of days. I've had harvests that I haven't used for two weeks, and they took off fine without giving them a drink of starter. I'm just curious if there's any detrimental effects of such a lapse between uses.

These are by no means critiques of the cold pitching practice, but just the way that I've been going about things. I've been very happy with the results, but if what I'm doing isn't giving me the best results possible, then I'd like to change them up!

Offline BeerSmith

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Re: CJ's Cold Pitching Theory
« Reply #3 on: November 11, 2003, 11:41:27 AM »
I guess I will have to give this a try on my next batch....

Thanks!
Brad
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cj_in_j

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Re: CJ's Cold Pitching Theory
« Reply #4 on: November 11, 2003, 07:03:01 PM »
Quote
Once the yeast settles out, it's probably about 1.25-1.5 cups of solid yeast. Is this too much to pitch? I see you say to use about 1 cup of slurry... am I overpitching? I've never seen quite as fast a start as you describe--2 to 4 hours--but things are usually moving with 8-12 hours.

Another thing: I see you recommend using the harvested yeast within a couple of days. I've had harvests that I haven't used for two weeks, and they took off fine without giving them a drink of starter. I'm just curious if there's any detrimental effects of such a lapse between uses.

I think partially you answered your own question. If you're keeping your harvested yeast for a week or two, the number of viable healthy yeast cells decreases quite a bit. As such, it'll take the yeast longer to multiply to fermentation quantities, and that's probably why you're seeing 8-10 hours of lag time instead of 2-4. I would say that if you're pitching 1.5 cups of "old" slurry, then you're probably pitching the right amount of live cells, or maybe even underpitching, depending on how long the harvested yeast has been sitting around in the fridge. Have you tried pitching the next day?

Also, note that I said 1-1.5 cups. It really depends on the starting gravity. With a low-gravity beer, up to 1.045 or so, 1 cup of fresh slurry should be fine. Medium-gravity beers, up to 1.065 or 1.070, should be fine with 1.5 cups. If you're brewing larger beers than that, go up to 2 cups. I just made a 1.100 OG beer, and I pitched 2.5 cups of slurry -- and it started blowing off within 8 hours. One final point, it's really hard for a homebrewer to overpitch. One of the ways is if you pitch fresh wort on top of the complete yeast cake from your previous batch -- that can lead to serious overpitching, which can lead to lots of yeasty off-flavors. But, other than that, you don't need to worry too much.

It also could be that we're defining lag time differently. When I say activity within 2-4 hours, I'm talking about positive pressure in the air lock, where the air lock starts pushing up and maybe releasing a bubble every minute or so. I'm not talking about constant or vigorous activity.

Hope that helps clear up a couple of your questions/comments. This is what works for me, based on my homebrewing experience and my experience helping out in the brewpub. Is it the best way? I don't know. But, I do know that if you treat your yeast with care and respect, your yeast will give you the best beer possible!  :)

Offline cmbrougham

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Re: CJ's Cold Pitching Theory
« Reply #5 on: November 12, 2003, 01:12:17 AM »
Great information--thanks cj. Your observations definitely make sense in what I've been seeing. I think what I might do from now on, is harvest 2 or 3 jars of slurry when I empty a primary--I'll collect less in each one than I have in the past. When it comes time to brew again, I'll step up the "mini-harvests" ALA a starter, waking the yeast beasties up and getting them ready for a night out on Wort Town. I've seen previous discussion re: starters, saying to pitch them when they're at their most active (i.e. high krausen). I'll start trying this with harvested yeast, and hopefully see more activity once pitched.

Once again, thanks!