3 Packs US 05?

Hope to brew 2 5 gallon batches Sunday.
I don't have the capacity for 2 starters.
Last time I brewed the same IPA recipe I'll be brewing Sunday I pitched 2 rehydrated us 05 packs, but came in 1.3 under target abv and had a bit too much sweetness.
I'm assuming I under pitched.
I tried several configurations in brewers friend pitching calculator. Even with 3 packs of 05 I come up short by 90 billion cells.
I'm thinking this assumes a dry pitch maybe?
I came close with 2 packs, I've got to think 3 would put me where I need to be.
So finally my questions, is 3 rehydrated packs too much?
What detriment might come from adding more?
Maybe 2.5 packs?
I and everyone who tried this recipe last time thought it was fantastic, and it was pretty damn good, I just want to ensure that I'm getting the very best that I can out of it this time...

 

What's the OG going to be?

 

Go with 3 rehydrated packs, it reduces clumps and helps with early activity

 

Not clear if you are talking about having enough to pitch 2 brews or one. I did a 5 gal IIPA with OG 1083 and Mr. Malty said I needed 1.7 packs of 11.5g (standard US-05 pack). If this is just for a single batch, you shouldn't need more than 2 packs unless you have crazy high OG. Be sure you are looking at a 11.5g calculation and not a 5g calc. If you are talking about sitting the yeast between 2 batches then, yes, you probably want 3 packs.

 

Approximately 1.085

I'm not gonna have another chance to brew anytime soon so 3 packs of 05 is the direction I'm going at this point.

 

I used 3 packs for a beer at 1.100 OG and the thing skyrocketed. Not sure if this will help either but I brewed a Belgian Stout with a slap pack of Belgian Yeast and a pack of US-05 with a beer at 1.089 OG and the batch turned out really efficient.

I personally think you will be fine with 2 packs, especially if it's rehydrated.

 

This is 2 batches, a stout and an IPA.
I'll be starting a starter for the stout in the morning.
I have one stir plate (completed and tested 1.5 hours ago!!!) and one flask.
I could do a starter in a growler like in the past, but I'll be filling them both at an event Thursday.
I'm gonna buy 3 packs of 05. I'll decide just what I'm gonna pitch between now and sunday

 

Using http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/ yeast calculator, you're going to need at least 2 packets of of dried yeast per 5 gallons of a 1.085 beer. Make sure to rehydrate them properly (90-100F water for 15-30 minutes), aerate the crap out of them, and make sure the temperature is low at first (62-65F), but as fermentation finishes, allow it to go up to 70-72 to finish.

 

I guess I really wanna know if pitching 3 rehydrated packs would cause any problems, like from too much yeast.
If not I'll probably do so and hope that this one ferments out a little further

 

No, that wouldn't cause a problem. You can over pitch yeast, but to over pitch that would be a TON of yeast.

With a beer that big, it's safer to err on the side of caution and provide a large amount of yeast to get the job done.

 

According to Safale's website, a packet of US-05 only contains 65 billion cells. I'd say that you won't be over-pitching with 3 packets.

 

Over pitching by a factor of two will decrease bitterness and esters. Under pitching by a favor of two will increase esters. (see mbaa paper on beer quality and pitch rates)

However, a difference in pitch rate by a factor of five can still make good beer. The two are just noticeably different. (See brulosopher exbeeriment)

Dry yeast is 20 billion cells per gram. Rehydrated in wort will yield about 50% viability. Rehydrated carefully following the manufacturer's directions will yield about 90%.

 

Just curious where you are getting your numbers from. And if they are correct, why would Fermentis understate their count of viable cells?

 

Fair questions. Fermentis provides a very conservative minimum viable cell count. (assuming you are talking about the 6 billion Viable cells per gram here: http://www.fermentis.com/wp-content/uploads/2012/02/SFA_S04.pdf) 20 billion Total cells per gram is what I have observed ( see here http://www.woodlandbrew.com/2013/01/how-many-cells-are-in-package.html). It is also the number I have seen in every scientific paper I have read that makes the conversion.

The rehydration viability percentages are ball parks based on what I have seens as well as what I have read. If you google around you'll see some pretty wide spread numbers. Here is one data point:
http://www.woodlandbrew.com/2013/02/rehydrating-safbrew-yeast.html

 

Very informative. Thank you very much for your input.

 

I'd be interested in what your mash temp was (too high?). I'd think that 2 packets of US-05, rehydrated would do just fine on a 1.085 beer. If I was brewing a beer that big, and looking for it to be dry, I'd aim for 148F on my mash (150F on the outside).

 

1. go here:
http://www.mrmalty.com/calc/calc.html

2. type in 1.085 in the OG.

3. type in the amount of beer you have (5 gallons exactly?)

4. click on the dry yeast tab.

5. make sure you read the "# of 11.5 gram dry yeast packs."
which should say 1.4 if you've typed in 1.085 and 5 gallons. the calculator is already assuming 90% viability for you.

if you pitched two packets last time, you already overpitched by something like 90 billion cells. i have to agree with the rest that your problem is not the yeast.

 

Thanks you guys