How much yeast do you REALLY need?

[jldc]

I've read all of these threads about how much yeast you need to pitch. One of the links actually said you would need a 2.5 gallon starter for 5 gallons of beer (the point was that most people don't pitch enough yeast).

Obviously, people get reasonable results with a single pkg of dry yeast or a tube of liquid yeast. Is seems that for liquid yeasts in particular a starter may be a good idea (500ml of wort for 24 hrs or so). For dry yeast, just pitching 2 pkgs seems like a good idea.

Does this sound like a reasonable approach?

 

[Tenchiro]

Mr Malty Pitching Rate Calculator is a pretty good calculator for it. For my own brews I generally use an 11g pouch of dry.

 

[Edcculus]

Mr. Malty Pitching Rate Calculator

The anwser is that it depends on your starting gravity. The higher the gravity, the more cells you need. A 2.5 gallon starter is a bit much for a regular ale. If you are making a higher gravity lager though, thats about right.

 

[Austinhomebrew]

You need at least 10g of dry yeast for a normal gravity 5 gallon batch of beer. If your beer is above 1.065 OG go for at least 20g.

Same with liquid, use one tube below 1.065 and 2 above.

Breweries use the equivelent of one tube per gallon. This is easy for them to do.

There are going to be people that will post after this that will say "I have only used 1 tube on a high gravity beer and it worked fine".

Of course it fermented with one tube but you are putting a strain on the yeast that will produce some minor off flavors.

If you want your beer to taste its optimum best don't underpitch.

Forrest

 

[Kauai_Kahuna]

So after all the great technical answers I'll just use a Carl Sagon voice and say "Billions and Billions of yeast" per gallon.

 

[noremorse1]

My dick-head answer is search the forum/google/wiki. However, I am high on prescription pain killers from surgery... so I am in a more favorable mood.

4 billion cells for each point of OG when pitching into a little over 5 gallons of wort. If you want a quick way of doing a back of the envelope estimate, that is really close to 0.75 billion cells for each point of gravity per gallon of wort. Double that to 1.5 billion for a lager.

A White Labs tube has between 70 and 120 billion cells of 100% viable yeast

A Wyeast Activator pack (the really big ones) and the pitchable tubes have an average of 100 billion cells of 100% viable yeast

Most dry yeast has an average cell density of 20 billion cells per gram. You would need about 9.5 grams of dry yeast if you were pitching into 5.5 gallons of 1.048 wort to get the proper cell counts.

Source: Mr Malty

 

[david_42]

I've never had a problem with a single 10-11 gm packet of dry yeast in 5 gallons. For anything over 1.080, I brew a lower gravity batch & pitch on the cake.

 

[Bob]

Same with liquid, use one tube below 1.065 and 2 above.

Breweries use the equivalent of one tube per gallon. This is easy for them to do.

If you want your beer to taste its optimum best don't underpitch.

If I might take the liberty of disagreeing with you, Forrest, the equivalent of one tube per gallon is underpitching.

The rule of thumb is one million active cells per milliliter per degree Plato. Thus, for five gallons/19L, we need 19 billion cells per degree Plato; if we presume 12°P - or 1.048 - we need 228 billion cells at pitching for a nominal pitch. Neither Wyeast nor White Labs provide that many cells in a packet or vial; at least Wyeast promises half that in an Activator(tm) pack; White Labs has never shown me more than 80 billion cells per vial, no matter how fresh the sample.

The brewery standard is 1 pound of slurry per barrel of wort at 12°P. That's a hell of a lot more yeast than a "vial"; it's more like 3 vials, practically speaking. Even at White Labs's best case - 150 million cells per vial - it's the better part of two vials. And that's at 1.048, not 1.065.

Respectfully,

Bob

 

[Bobby_M]

... which is also why breweries are able to turn over their beers so quickly. More yeast, less time to ferment and condition before it's off to the filters.

 

[ajf]

See MB Raines, Ph.D. - Guide to Yeast Culturing for Homebrewers - Maltose Falcons Home Brewing Society (Los Angeles Homebrewing)

-a.

 

[nukebrewer]

I found this while trying to figure my pitch rate for my brew today. It helped me to be OK with my 220 billion cells when the calculators say I need 270.

 

[Bob]

... which is also why breweries are able to turn over their beers so quickly. More yeast, less time to ferment and condition before it's off to the filters.

On the contrary, Bobby, I often experience faster fermentations at home than I ever did in a brewery or brewpub, and I assure you I do not overpitch.

Breweries can shorten the conditioning/settling portion of the ferment through more means than mere overpitching. Crash-chilling and tank fining mean far, far more to conditioning/settling than does a surfiet of yeast. Besides, if you do the math, 1 lb slurry per bbl at 12°P is near enough to the one million active cells per milliliter per degree Plato as makes little difference.

Pitching an excess of yeast does not mean less time in the fermenter. It does mean lack of ester profile, curtailed biological cycle and great potential for yeast-bite off flavors.

Cheers,

Bob

 

[Pelikan]

The simple answer: Get a stir plate (or build one), buy a 1-liter flask, fill it with 1 liter of wort plus nutrients, pitch one vial or activator of liquid into this, cover with a loose-fitting foil cap, stir for 24 hours, and pitch that into your 5 gallon batch. You'll have anywhere from 200-300 billion cells (which is what you'll need for most any ale).

If you don't want to mess with liquid and/or a starter, get a packet or two of dry yeast, properly reconstitute, and pitch.

If you want proper pitch rates, it's as simple as doing one or the other method.

 

[tabaruf]

would a 6g packet of dry yeast be enough to ferment 4 gal of 1.043 wort?

 

[ajf]

From http://www.mrmalty.com/calc/calc.html you need 7g dry yeast. 6g would be slightly short, but IMHO not enough to worry about.

-a.

 

[usfmikeb]

Mr Malty Pitching Rate Calculator is a pretty good calculator for it. For my own brews I generally use an 11g pouch of dry.

Yep, a single 11 gram packet is generally going to be enough for just about any batch. If doing a really big beer, a second packet won't hurt. I stopped making starters when I started using dry yeast, although I do hydrate it before pitching, using some quickly cooled wort that I pull off ten minutes into the boil.

 

[ChaosStout]

I will say that I hate making starters. I end up using 2 vials of yeast per 5 gal batch. Its an extra $6.50 but saves me the hassle of making a starter.

 

[cwi]

Yep, a single 11 gram packet is generally going to be enough for just about any batch. If doing a really big beer, a second packet won't hurt. I stopped making starters when I started using dry yeast, although I do hydrate it before pitching, using some quickly cooled wort that I pull off ten minutes into the boil.

You could save yourself even more hassle, and have healthier yeast, by hydrating with plain water. The information on this is readily available. The only hydration additive the yeast makers recommend is some overpriced fairy dust they sell, which is just dead yeast or something.

 

[gr8shandini]

I found this while trying to figure my pitch rate for my brew today. It helped me to be OK with my 220 billion cells when the calculators say I need 270.

I'd love to see the full text of this article. The following statement is definitely intriguing:

It was also found that higher pitching rates led to lower bitterness unit levels in the resulting beers (possibly due to the uptake of bitter substances by yeast cell walls and/or to increased foaming during fermentation) and lower free amino nitrogen (FAN) utilization rates, leaving higher residual FAN levels in the beers, as well as higher levels of ethanol and fusel alcohols and lower levels of esters and other volatile organic compounds, with consequent differences in beer flavour. Lower pitching rates were found to result in higher intensities of the overall aroma and of hoppy and fruity aroma notes in the finished beer.

I happen to like hoppy and fruity aromas over fusel alchohols. If this is correct, it seems to me that overpitching is a bigger hazard than underpitching.

 

[toxdoc49]

I know this thread is old, but if I have an OG of 1.082, then I want to (maybe, or for good measure), use two packs of dry yeast or two packs of Wyeast. I have a recipe for an imperial IPA but there was no mention of yeast type or amount to use.

 

[fendersrule]

I pitch 1.5 packets of US-05 for all normal gravity beers I make (5 Gallons). I get superb attenuation rates (depending on my mash temps, I've gotten 95% attenuation if I mash low enough). No off flavors that I or other more "pro" brewers could detect.

If I go the the hassle of re-hydrating then I use 1 packet of yeast. I tried re-hydrating before and didn't notice any difference in lag time or taste.

If I'm making something higher gravity such as 1.082, I pitch two packets.

Sticking with 1.5 packets for me works well as a general rule of thumb because I always end up with 2x 5 gallons of wort after every brew day, so I limit myself to only buying 3 packets of yeast to assure I get great performance!

As always, I make sure to warm up the packets of yeast by sticking them in my pocket for a little bit, and I make sure my wort is always in the "ideal" range before pitching!

 

[gbarba2]

I've read all of these threads about how much yeast you need to pitch. One of the links actually said you would need a 2.5 gallon starter for 5 gallons of beer (the point was that most people don't pitch enough yeast).

Obviously, people get reasonable results with a single pkg of dry yeast or a tube of liquid yeast. Is seems that for liquid yeasts in particular a starter may be a good idea (500ml of wort for 24 hrs or so). For dry yeast, just pitching 2 pkgs seems like a good idea.

Does this sound like a reasonable approach?

Oh come on people, has anybody ever taken Biology? It's like a petri dish...any amount of yeast will do! It multiplies rapidly and soon becomes a huge colony! Even if you use just like 1/4 teaspoon, you're good to go.

 

[dmtaylor]

Almost all homebrewers are overpitching by about a factor of 2-3. Relax. Don't worry. Pitch less. Be happy.

 

[RM-MN]

Oh come on people, has anybody ever taken Biology? It's like a petri dish...any amount of yeast will do! It multiplies rapidly and soon becomes a huge colony! Even if you use just like 1/4 teaspoon, you're good to go.

The problem with under pitching greatly is that the little bit of yeast you add may be competing with some bacteria that are also multiplying rapidly and can affect the flavor of the beer. By pitching at or near the proper amount the yeast quickly change the conditions of the beer to stop the bacteria from multiplying.

 

[shetc]

Things have changed since the original post. Most of my brewing friends are now using Imperial or Omega liquid yeast, and these are good to go straight out of the pouch, at least for normal gravity beers. I have good results even for lagers without requiring a starter (obviously freshness is required). Single 11g packets of dry yeast are still the norm, but rehydration is no longer recommended, at least according to Fermentis. And kveik is a whole 'nother thing - I have made great regular strength beer with 1/2 teaspoon of Omega Hothead for a 5 gallon batch. Science moves on.

 

[mattdee1]

I have made great regular strength beer with 1/2 teaspoon of Omega Hothead for a 5 gallon batch. Science moves on.

^^ that sounds crazy, but somehow I'm not remotely surprised.

On that note, am I the only one who thinks the Mr. Malty calculator is kind of useless? I guess it’s a nice tool to look at as a purely academic exercise, but in a practical, hands-on homebrewing situation I strongly question whether there is any objective benefit to following its recommendations. I suppose it’s a great way to get yourself spending too much money and time on yeast, but what else?

I know anecdotes aren’t very useful either, but I feel the need to share this particular one. Recently, I took a single pack of WLP yeast that was less than a week from its expiry date and dumped it directly in a batch of ~12°P wort. This was half of a 10 gal batch, and I figured there was a risk it would end up sucking due to “poor yeast pitching practices” but if I wanted to do an impromptu brew on that day then pitching that pack directly into the fermentor was the only option I had. So, I decided to roll the dice and see what would happen.

It may have taken a bit longer than usual to take off, but take off it did, and the beer is perfectly fine. Very good, even.

I think when I checked Mr. Malty after the fact to see what I “should have” done, it said that with the age of the yeast, I would need to make a 1L starter with seven vials – that’s not a typo; seven vials – to achieve the “correct” pitch rate. When one compares that recommendation to what I actually did and the results I got, I think it’s fair to say the recommendation is revealed as utterly useless information.

I’m not saying I plan on adopting the above pitch rate as standard practice, but I mention this anecdote as an instructive case that strongly favors the RDWHAHB side of the OCD spectrum.

Probably an unpopular opinion, but I kind of wish everyone would stop posting links to Mr. Malty as a knee-jerk response to pitch rate questions. I think more direct guidelines based on personal experience are much more useful, no matter how much they deviate from what Mr. Malty says.

 

[dmtaylor]

am I the only one who thinks the Mr. Malty calculator is kind of useless? I guess it’s a nice tool to look at as a purely academic exercise, but in a practical, hands-on homebrewing situation I strongly question whether there is any objective benefit to following its recommendations. I suppose it’s a great way to get yourself spending too much money and time on yeast, but what else?

I know anecdotes aren’t very useful either, but I feel the need to share this particular one. Recently, I took a single pack of WLP yeast that was less than a week from its expiry date and dumped it directly in a batch of ~12°P wort. This was half of a 10 gal batch, and I figured there was a risk it would end up sucking due to “poor yeast pitching practices” but if I wanted to do an impromptu brew on that day then pitching that pack directly into the fermentor was the only option I had. So, I decided to roll the dice and see what would happen.

It may have taken a bit longer than usual to take off, but take off it did, and the beer is perfectly fine. Very good, even.

I think when I checked Mr. Malty after the fact to see what I “should have” done, it said that with the age of the yeast, I would need to make a 1L starter with seven vials – that’s not a typo; seven vials – to achieve the “correct” pitch rate. When one compares that recommendation to what I actually did and the results I got, I think it’s fair to say the recommendation is revealed as utterly useless information.

I’m not saying I plan on adopting the above pitch rate as standard practice, but I mention this anecdote as an instructive case that strongly favors the RDWHAHB side of the OCD spectrum.

Probably an unpopular opinion, but I kind of wish everyone would stop posting links to Mr. Malty as a knee-jerk response to pitch rate questions. I think more direct guidelines based on personal experience are much more useful, no matter how much they deviate from what Mr. Malty says.

I actually use Mr. Malty so that I know how much is too much. I will only ever use one pouch of yeast regardless of his recommendations, and if able to force that into his calculator, then I'll use it to calculate how big a starter he thinks is needed... and then divide that answer in half to get the realistic amount that I should pitch. So, in that respect, for getting into the ballpark but then dividing by 2, I find the calculator somewhat useful actually.

 

[fendersrule]

Over pitching is far better than under pitching for many reasons. Also "truely" over-pitching on a home brew level is very difficult.

I feel like the many different opinions on pitching methods/amounts is just for making the individual sleep better at night--not saying that's a bad thing.

 

[tellyho]

I pitch what I have - packet of dry or pouch of liquid. I never make starters. I'm happy with my beer.

 

[Carolina_Matt]

Interesting. I've always used dry yeast because I thought you needed a starter with liquid. If you can directly pitch liquid yeast, I may have to give it a shot. Although at ~$2.50/pouch, it's tough to beat Safale US-05 for most of my brews.

 

[BrewnWKopperKat]

Over pitching is far better than under pitching for many reasons.

What would the pros/cons of over/under pitching be?

Also "truely" over-pitching on a home brew level is very difficult.

What amount of yeast would be a "truely" over/under pitched amount of yeast (assume a 5 gal batch)?

 

[fendersrule]

I expect people with more experience to answer most of your questions better. I've only made 30 batches but have used all types of yeast.

Under pitching is severely worse because longer lag time (more chance for infection) and more yeast stress leading to off-flavors. Over pitching on the home brew level (not in the "technical sense" but the "let me throw 2 packets in here instead of 1 packet" sense) = ZERO cons other than a few extra bucks in price. Over-pitching from a technical term (when you are REALLY over pitching which is HARD to do on a home-brew level) someone else can answer. Probably off flavors of sorts, but two packages of US-05 ain't going to do that. I don't even expect that three packets would either.

Be careful with some of the liquid yeasts. The little "packs" sometimes don't have the CFU count than a package of dry yeast would have (it still works fine as I found out, just a longer lag than what I'd like). Like always, read the instructions that come with your yeast. When picking up a packet of dry yeast, I am more confident that the yeast is good since it's frozen. With the liquid stuff, it seems more volatile to the environment, shipping, aging, etc. Neither are better compared to each-other. I buy what the recipe calls for.

Go to the manufacturer's website and do what they recommend. Other yeast calculators are making a lot of assumptions. I'd trust the manufacturer of the yeast more than anyone else. Some of them have OG calculators that tell you how much yeast to use. White lab prints an OG range right on their liquid packets. I do whatever that says.

 

[bleme]

I used 1 gram of dry Aurland #38. It took 22 hours to really get going, but made 5 gallons of fine beer...

 

[jgmillr1]

Dry wine yeast is typically pitched at a rate of 1g/gal and it's S. Cerevisiae like ale yeast. Proper rehydration is necessary as well as using yeast under 1 year old to avoid stuck fermentations. And these yeasts will ferment a 1.09 SG wine dry. So, I'm not seeing why the dose rate needs to be higher in beer.

 

[Qhrumphf]

Oh come on people, has anybody ever taken Biology? It's like a petri dish...any amount of yeast will do! It multiplies rapidly and soon becomes a huge colony! Even if you use just like 1/4 teaspoon, you're good to go.

Sat through a 20 minute random "biology" video on YouTube and am now a microbiologist. Took elementary school social studies and know everything about how government works.

Sit down before you hurt yourself.

Ultimately unless you're using a microscope and counting cells, it's all guesswork. Regardless, some strains/families (ie Kviek) do well with ridiculously low pitch rates. Most do not. Don't oversimplify it.

 

[Farside]

When I'm running multiple batches in a row, I'll pitch the entire yeast load from the previous batch into the new batch.

When I'm starting a batch with fresh yeast, I always start the yeast from a 5g packet for a period of time to grow it out. For a 5 gal batch it might be only 48 hours. for a 12 gallon batch it will be 3-5 days.

 

[BrewnWKopperKat]

I know anecdotes aren’t very useful either, but ...

... agreeing with (and perhaps building on) the anecdotes comment ...

I'm finding that anecdotes may lead to curiosity
which may lead to more casual observations
which may lead to controlled observations
which may lead to reproducible controlled observations
which may lead to more casual observations ...

I don't see how one can have "brewing science" without casual observation.

 

[shetc]

My personal experience is undoubtedly anecdotal as I am not collecting data of any sort. I do like the data collected by Brulosophy though it is mostly 1 off experiments. I switched to Imperial because of their success with that product.

For example, http://brulosophy.com/2019/03/28/ye...ter-in-an-amber-ale-the-bru-club-xbmt-series/

 

[mattdee1]

Under pitching is severely worse because longer lag time (more chance for infection) and more yeast stress leading to off-flavors.

^^ See, these are exactly the types of "established facts" that had me expecting that my batch of sorely under-pitched beer would end up sucking, yet, somehow, some way, it was completely fine.

The infection fighting benefits of a short lag time make a lot of sense intuitively, and for that reason alone I generally shoot for making starters with liquid yeast to shorten the lag time. But even there, I'm guessing that half-decent sanitation practices would more than buffer against a few extra hours of lag time. A lag time of over 24 hours certainly didn't matter in my recent experience.

As for under-pitching causing "yeast stress," this is one of those things that I have read a thousand times on forums and have just accepted as a real thing with real impacts on my beer because, well, it must be a real thing otherwise people wouldn't be talking about it all the time... right...?

Now, I'm not saying it's not a real thing; my concern is that the propensity for rote repetition of such nuggets of wisdom is out of proportion with the actual threat posed, which ultimately isn't very helpful to any of us. How many of us can:

1) claim to have direct experience with adverse effects in their beer that are directly attributable to "yeast stress due to under pitching." Surely it will be dependent on yeast strain, so for argument's sake, let's take a dirt-common yeast like WLP001 or US-05.

2) describe what the yeast stress effects actually do to the beer. Not theoretically using a bunch of esoteric biology jargon, but a real-world, qualitative description. If I have a basic beer like a blonde ale, which is light-tasting by design and will not be able to hide the markers of fermentation flaws, what will the markers of "yeast stress" taste like?

I'm genuinely curious here, not being a smart ass.

I have used those yeasts dozens of times, often in defiance of suggested pitching rates. Yet, it would be flat out deceptive of me to claim that I can speak on either of these points from direct personal experience.

 

[odie]

I did an RIS on a single dry packet of US-05. Very high OG. I ended up with 14%. One pack is all you probably will ever need on any beer.