Can you pitch too much yeast?

Going to try a starter next time around. Figured I would try to err on the high side - just checking the consequences of over-pitching.

Cheers!

Yes, you can. Generally attributed to a dull beer. Shoot for +/- 20%.

jsv1204 said:

Going to try a starter next time around. Figured I would try to err on the high side - just checking the consequences of over-pitching.

Cheers!

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Go to yeastcalc.com or mrmalty.com
Plug in the numbers and you'll see what size starter you need, takes all the guesswork out of it

Go to yeastcalc.com mrmalty.com
Plug the numbers and there is no guesswork, it will tell you what size starter you need

I think (read, I'm not positive) that if you overpitch on a yeast that provides a lot of flavor and aroma to the beer you could see some consequences from doing so. From what I gather most of those flavors and aromas are by byproducts of the yeast reproduction during the lag phase and early fermentation and if there are already a ton of healthy yeast cells they will not need to reproduce as much, therefore leaving less yeasty aromas and flavors. Now if it's a super clean and neutral yeast, I think you're alright.

This is my thinking. Please someone smarter than me correct me if I'm wrong....

cmybeer said:

I think (read, I'm not positive) that if you overpitch on a yeast that provides a lot of flavor and aroma to the beer you could see some consequences from doing so. From what I gather most of those flavors and aromas are by byproducts of the yeast reproduction during the lag phase and early fermentation and if there are already a ton of healthy yeast cells they will not need to reproduce as much, therefore leaving less yeasty aromas and flavors. Now if it's a super clean and neutral yeast, I think you're alright.

This is my thinking. Please someone smarter than me correct me if I'm wrong....

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Yeah, that's basically it. Overpitching will significantly alter the initial growth phase of the yeast, which normally will contribute important beer flavors.

Everything I've read/heard has said that while you can indeed overpitch, it's actually very difficult to do on a homebrew scale unless you're putting your wort directly on top of a yeast cake (and even then, I've done it a couple times in a pinch with no issues, however only with 1056, never something particularly phenolic or estery. YMMV). Yeasties are much more forgiving of overpitching than they are underpitching. So basically, I wouldn't worry too much about overpitching.

I'd say you could double the recommended starter size and not be overpitching, or at least not pitching so many yeast that it will have a negative effect on the flavor. Much easier to underpitch than to overpitch, imho.

I tend to error on the side of over pitching than under pitching. Since your basically making and educated guess on the viability of your liquid yeast and the growth in the starter.

Thanks for the info, all - cheers!

Extreme overpitching can very much so create an explosive fermentation. I pitched a very low grav beer (1.035) onto a full yeast cake and within an hour had fermentation start up. two hours later had to add weight plates to my brew bucket to ensure it didn't get blown off. The beer turned out great, but I lost a full gallon to the blow off tube. I didn't have any yeast off flavors and this is a pale beer that wouldn't hide such tastes. So unless you're going to pitch a ton of yeast, I wouldn't worry about the flavors but I would strongly suggest a blow off tube.

Unless you go crazy, you probably won't notice an overpitch in the flavor - at least I don't.

However, overpitching does result in less than perfectly healthy yeast at the end of a brew just like underpitching does. Not a big deal if you are just going to toss the yeast, but it could be a significant complication if you are reusing it from batch to batch.

FWIW, i recently pitched a 1L starter of Wyeast 3068 into 4 gallons of session hefe. The flavor profile is too clean for a hefe and i think it directly relates to me overpitching. I made the starter before we undershot our gravity otherwise per, Mr. Malty, i would have been fine pitching a lone smack pack unaltered. So like said above, over pitching a flavorful yeast will not bring out the esters/phenols you are trying to achieve with that paticular strain.

SledgeH said:

Extreme overpitching can very much so create an explosive fermentation. I pitched a very low grav beer (1.035) onto a full yeast cake and within an hour had fermentation start up. two hours later had to add weight plates to my brew bucket to ensure it didn't get blown off. The beer turned out great, but I lost a full gallon to the blow off tube. I didn't have any yeast off flavors and this is a pale beer that wouldn't hide such tastes. So unless you're going to pitch a ton of yeast, I wouldn't worry about the flavors but I would strongly suggest a blow off tube.

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Just made a 1 gallon "test" beer to see how difficult it is to make a 10% + ABV beer and this is exactly what happened. Over pitched and basically had a blow off explosion even with the blow off tube, would have benefited by having the vent tube go into a bucket rather than a soda bottle but lost 1/4 gallon through the blow off tube... fun to watch, definitely didn't need a yeast starter with a 1 gallon batch though.

I make one same beer every 14 days. I carefully calculate the harvest needed, say screw this, and then just dump on trub, set in the fermenter chamber at 62°. The blow off hose (puke tube) is routed to a empty carboy. This eliminates the need to care about how much blow off you get and if I get a gallon I bottle it. This has worked for years and for this particular flavor of ale eliminates the need to buy yeast. Sometimes I even use the trub from the blow off for a different beer.

Figured i'd bump this thread instead of starting a new one.

Is the same principal true for dry yeast?

I rarely need a full 11.5g pack of dry yeast (which is all my LHBS sells), sometimes MrMalty calculates it at half that, but I always pitch the full packet as I do not know how to store dry yeast for extended periods of time once the packet has been opened.

I personally think the benefits of not underpitching far outweigh the negatives of potential overpitching.

RayOhm said:

Figured i'd bump this thread instead of starting a new one.

Is the same principal true for dry yeast?

I rarely need a full 11.5g pack of dry yeast (which is all my LHBS sells), sometimes MrMalty calculates it at half that, but I always pitch the full packet as I do not know how to store dry yeast for extended periods of time once the packet has been opened.

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Considering that not all the cells are viable and if you're pitching directly onto the wort many more will die off, pitching a whole packet of dry yeast will do you just fine

Yes it is possible to over pitch any type of yeast. Over pitching yeast can cause less of an optimum growth phase of the cells and more cells
May prematurely die off because there is not enough food available as the cells grow and replicate.

Dry yeast can be sealed up and stored in the fridge or just buy the smaller pack if that is typically the amount you need.

I guess it's also personal opinion from experience. I have pitched onto a yeast cake from another batch, which had likely 5-10 times the amount of yeast I needed. The beer came out great, and it was likely a little better than the first back of the same stuff. The first batch was a pack of dry yeast. I think the first batch has a little off-flavor, which I'm assuming could be a slight underpitch.

Some people think mrmalty calls for more yeast than necessary. I tend to agree with the more is better philosophy. Now, granted, I don't recommend using a full yeast cake, but I think growing large starters or rounding up my dry pack count makes sense. I usually calculate the amount I need, but I am very conservative with the viability estimate for the original yeast. I error on the overpitch side.

I pitched an english mild onto a whole yeast cake of Safale S-04. There is plenty of yeast character present.
Works great, no problems at all.

I had the same question today and I'll report back in a couple of months with my results. I just grew a 240 billion cell starter of WLP001 for an IPA with an estimated post boil gravity of 1.065. This is only my second all grain batch, so I'm not totally dialed in yet and I ended up at around 63% efficiency with a 1.055 post boil according to my hydrometer. Am I going to over pitch? Probably. Am I worried? Not really, because it was an awesome late summer brew session in the northeast. Cheers!