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Old 09-06-2008, 07:44 PM   #1
Jbileau8090
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I have a batch that is 6 days in the primary. I made a starter with dry yeast, and it was really humming when I pitched it. My airlock was bubbling like crazy in a matter of an hour or two, and pretty much still in 36-48 hours. This was the fastest fermentation has ever stopped/slowed for me. Assuming that my gravity readings turn out ok tomorrow, is there any benefits/disadvantages to a quick fermentation? Is it possible to over pitch? Should I make a starter with liquid yeast only? Any thought? thanks

 
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Old 09-06-2008, 07:50 PM   #2
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Three things.

It's virtually impossible to over pitch yeast.
Do not make starters with dried yeast.
Fermentation can be done in 24-48.
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Old 09-06-2008, 09:35 PM   #3
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After pitching and prior to the start of fermentation, yeast cells are multiplying and producing compounds that, in the right amounts, make ales flavorful. Pitching too much yeast can mean less yeast growth and result in a cleaner tasting beer that might not fit a given style. So, it's not the end of the world, but it's best to pitch the "right" amount of yeast.
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Old 09-06-2008, 09:49 PM   #4
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Overpitching can be a bad thing.

Chris White of White Labs says:

Quote:
If the beer is overpitched, yeast do not grow though a complete growth cycle. This results in few new yeast cells, which makes for unhealthy yeast and low viability by the end of fermentation.
Thus, if you intend to harvest and repitch, or if the yeast run out of steam and crap out before the intended attenuation is reached, you may be in for problems. Also, as menschmachine noted, the flavor/aroma profile of the yeast may be adversely affected. The reproductive cycle of the yeast is when the esters, phenols, and other flavor precursors are produced.

In my opinion, most homebrewers underpitch. The risks from underpitching are much greater than the risks from overpitching, in extended lag times, weak reproduction, insufficient fermentation power, and too much ester production.

Here's a bit from beeradvocate.com that states the remaining concerns nicely:

Quote:
From what I understand, the issue with overpitching has to do with the same biological survival mechanism that brings us attenuation. When yeast reach a point where there is no longer enough food to sustain their numbers they go dormant and wait for more food to be introduced. Now, overpitching becomes an issue if the ratio of cells to food is too low. This will cause incomplete or stalled fermentation as the yeast will drop out of solution and wait for more food. Additionally, they seem to stop reproducing once they reach a point where they can no longer sustain. So say your first beer had a starting gravity of 1.050. If you took a cup of that slurry and repitched it into another wort of equal gravity they will reproduce to roughly the same number of cells as was the final number of cells in the original beer.

As others have pointed out initial cell count will have its greatest effects in terms of chemical byproducts of reproduction, not fermentation itself, such as phenols and esters. This is why many recommend underpitching on hefeweizens; forcing the yeast to reproduce to environmental capacity from a small cell count maximizes the production of such byproducts.
It is best to pitch the appropriate amount of yeast, which is easily learnt by clicking on Mr Malty Pitching Rate Calculator and entering the correct information.

Your fermentation, J, is fine. Short lag times are a good thing. Rapid fermentations are a good thing. It might take a little while to completely flatline, so give it at least ten days in the primary before you go fiddling about with it.

Cheers,

Bob
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Old 09-06-2008, 10:11 PM   #5
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Quote:
Originally Posted by orfy View Post
Three things.

It's virtually impossible to over pitch yeast.
Do not make starters with dried yeast.
Fermentation can be done in 24-48.


Why not make starters with dry yeast? I did a starter the other day with dry yeast and pitched it yesterday.

Thanks
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Old 09-06-2008, 10:20 PM   #6
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Quote:
Originally Posted by Blue View Post
Why not make starters with dry yeast? I did a starter the other day with dry yeast and pitched it yesterday.

Thanks
You can, it's not going to hurt anything. You just wasted time and DME/LME in doing so.
The dried yeast has enough yeast cells in a pack that a starter is not needed.
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Old 09-06-2008, 10:24 PM   #7
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What if your doing a big beer, 1.080+, wouldn't you want a starter then?

 
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Old 09-07-2008, 12:19 AM   #8
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Quote:
Originally Posted by jcarson83 View Post
What if you're doing a big beer, 1.080+, wouldn't you want a starter then?
Don't overcomplicate things. According to Mr Malty, you need 16g of fresh dried yeast to optimally ferment a 1.080 wort. Let's do the math, shall we?

All prices from Northern Brewer.

1 11g packet of US-05: $2.25

You need 1.4 packets of US-05 to optimally inoculate your 1.080 wort. So you buy two 11g packets and be damned to overpitching concerns. $4.50, plus tax, and you're done.

1 XL Wyeast "smack-pack" - $5.75

An XL smack-pack has ~100 billion active cells, which is less than the necessary 177 billion cells. You can buy another smack-pack and overpitch a bit, but that takes your yeast outlay to $11.50.

Conversely, you could build a starter of either yeast. Let's pretend you don't need to buy the equipment or spend another $4.99 for a pound of DME to build a starter. It's still careful planning, careful yeast handling, and lots of hassle, to save what? $2.25?

Me, I'd just grab another packet of dry yeast from the stash in the door of my fridge.

Cheers,

Bob
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Old 02-22-2009, 12:00 PM   #9
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Bringing up an old thread here. I've got an IPA in my secondary which i think I over pitched.

I had about a 2 liter starter (LOTS of yeast in there) for a 5 gallon batch and I had a crazy fermentation for two days and then it settled out. After I siphoned it to the secondary, adding a little Hallertauer for dry-hopping, I haven't seen a single bubble in the airlock for three days! The water in the airlock is almost levelled. My OG was 1.054 and my gravity was 1.018 when I siphoned. I see little, if any, yeast in there. I've never come across this kind of intense fermentation, so I'm quite worried and thinking what I should do (if anything at all). Is it worth it just waiting a couple of weeks and see if it clears out or should I add more yeast/wort?

 
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Old 02-22-2009, 12:15 PM   #10
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I wish I could answer your question, but I do know that the type of yeast is important to know. Some attenuate better than others, but 1.018 seems high for a F.G.

My advice, FWIW, don't worry and just wait. It's beer.

As far as what to do next time, NQ3X posted that handy calculator.
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