Yeast amounts

[hoppybrewster]

So I got this recipe book for Father's Day and all the recipes are 2 1/2 gallon batches. They all use full packs of yeast whether it be dry or liquid. All other ingredients are cut in half(assuming). So what gives with that? Should a guy be using 2 packs for 5 gallons?

 

[CastleHollow]

Depends on the starting gravity of the wort, but in general most yeast calculators will tell you that 1 packet/vial/pouch of yeast is under-pitching at 5 gallons.

 

[el_caro]

As Castlehollow has advised have a look at pitching rate calculators like Yeastcalc and MrMalty.
The amount of yeast you should pitch is determined by volume and OG of the brew and the age of the yeast.

Broadly speaking a Wyeast pack or a Whitelabs vial will only have around 100bn cells which will likely be just about right for direct pitching into 2.5 gallons.

An 11gm pack of dry yeast on the other hand if properly rehydrated at pitching time will give you around 220bn cells and as such will suffice for most 5 gallon brews of low to average OG. In other words pitching half a pack of dry or a one full liquid pack/vial for most 2.5g batches will be fairly close to ideal in most cases.

One 11gm dry pack will usually be right for 5 gallons but the best approach if using liquid yeast is to make a starter to boost the population and also to confirm viability of the yeast.

 

[hoppybrewster]

As Castlehollow has advised have a look at pitching rate calculators like Yeastcalc and MrMalty.
The amount of yeast you should pitch is determined by volume and OG of the brew and the age of the yeast.

Broadly speaking a Wyeast pack or a Whitelabs vial will only have around 100bn cells which will likely be just about right for direct pitching into 2.5 gallons.

An 11gm pack of dry yeast on the other hand if properly rehydrated at pitching time will give you around 220bn cells and as such will suffice for most 5 gallon brews of low to average OG. In other words pitching half a pack of dry or a one full liquid pack/vial for most 2.5g batches will be fairly close to ideal in most cases.

One 11gm dry pack will usually be right for 5 gallons but the best approach if using liquid yeast is to make a starter to boost the population and also to confirm viability of the yeast.

I've never done these calculations you speak of, just wonder if if been under pitching all these years. Tell me this then, can you over pitch? What if I just put two in every 5 gallon batch?

 

[incognitum]

Hoppybrewster -- this is what I do as standard procedure.

I always pitch two 11g packs of dry yeast into 5 gallons (usually Safale-04 or 05). I especially do this for beer with a higher SG, but I also do it on lower gravity beers.

What I get from this is peace of mind knowing that the fermentation is less likely to get stuck (mine never has), fermentation will start quickly and I don't have to worry about stressing the yeast and creating off flavors. And a big bonus, pretty much all my beers end around 1.012 -- even beer that is close to 7% ABV (which is the highest I've brewed so far). So I'm getting better attenuation and higher alcohol content by pitching an extra pack.

Sure, I could rehydrate 1 dry pack or do a starter with liquid, but I guess I'm lazy.

 

[paraordnance]

Hoppybrewster -- this is what I do as standard procedure.

I always pitch two 11g packs of dry yeast into 5 gallons (usually Safale-04 or 05). I especially do this for beer with a higher SG, but I also do it on lower gravity beers.

What I get from this is peace of mind knowing that the fermentation is less likely to get stuck (mine never has), fermentation will start quickly and I don't have to worry about stressing the yeast and creating off flavors. And a big bonus, pretty much all my beers end around 1.012 -- even beer that is close to 7% ABV (which is the highest I've brewed so far). So I'm getting better attenuation and higher alcohol content by pitching an extra pack.

Sure, I could rehydrate 1 dry pack or do a starter with liquid, but I guess I'm lazy.

You overpitching with 2 packs for gravities less than 1.060
Overpitching is a bad thing, just as bad as underpitching if not worse. Yeast has to go through certain stages to make good beer. Reproduction is one of them and its really important to pitch right amount of yeast not more and not less. If you pitch 2 packs of US-05 in 1.046 beer yeast don't have to reproduce at all, it will start consuming sugars right away thats why you have a quick starting fermentations. When yeast reproduce during a "lag phase" they set certain flavor profiles and produce esters which important to make good beer. The lag phase is usually around 12-24 hours depending on SG, yeast strain and wort composition.
I'm not saying you not going to make beer by overpitching and just won't be as great as one with proper pitch rates. Some people report bland, one-dimensional flavors when overpitching.

 

[kh54s10]

You can ferment a 5 gallon batch with one pack/vial. The problem is not whether it will ferment but whether you are producing optimal flavors. Pitching the proper amount of yeast for the gravity of the recipe being brewed. This can be done by pitching multiple packs of yeast, which can get quite expensive, or making starters. The DME required will cost less than the extra pack.

Dry yeast is designed to be used as is or by re-hydrating. Making a starter from dry yeast is counter productive. For a high gravity brew you may need to pitch more than one pack.

IMO, over-pitching is about as bad as under-pitching. Intentionally over-pitching is just a waste of money.

 

[incognitum]

To clarify, let me say that I have been pitching 2 packs of yeast into beer with a starting gravity of about 1.055 and higher.

I would not pitch two packs onto lower gravity beer. I haven't brewed anything with a starting gravity of less than 1.055 in several months, though, so when I say it's standard practice for me, I should say that it's standard on beers of 1.055 and higher, which is more in line with what a few of the commenters after me have said.

I do agree that it's a waste to pitch 2 packs onto lower gravity beer.

 

[incognitum]

When people talk about potential off flavors from pitching too much yeast, let me say that I haven't had much of an issue with that, however I did pitch 2 packs of Safale 06 Wheat yeast on a 5 gallons of Witbier and I do think it created a lot of off flavors. I can't describe what it is, but there is a harsh taste to it.

I have actually noticed trace amounts of this flavor in a couple commercial wit's that I've had recently. I believe it's a subtle off flavor from the wheat yeast... and since I added too much yeast, I got too much of that flavor. In small amounts, it tasted great. I just have too much of that flavor, whatever the hell it is.