Safale us-05 fail - what next?

[VictoryAle]

Hey all,
I fermented 3.25 gallons of an IPA (1.071 OG, mashed medium high) with 2 pkts of us-05. Second pkt was added two days after the first - I decided to add the second because I realized that technically I was underpitching, according to brewersfriend's pitching calculator, and because a krauesen had not formed.

2 days ago (5 days after initial pitch) the gravity was at 1.024. Since then I have agitated the wort a few times to rouse the yeast. Today it's still at 1.024 and judging by the appearance of the surface the yeast seems to be done. I definately want the gravity at least another 6-10 points lower. I could just go out and by a tried and true Wyeast smackpack but I have some slurry in my fridge that was harvested 3 weeks ago.

I have heard under two weeks in the fridge and you don't really need to wake slurry up with a starter. However, since I am really only looking to get rid of another 6-10 points I am thinking no starter would be fine. Sound realistic? Kind of not a big deal scenario, I know, but I just want to get this beer done ASAP, and my LHBS is closed tomorrow. What would you do?

 

[gilstein21]

i've never had an issue with US-05, but I usually leave it for a minimum of 3 weeks. I don't even check on it, or measure the gravity until then. I'm not sure how quickly it works, but I think it would have dropped a little more after the initial 5 days.

 

[Old_mil_guy]

What temp is wort at?

 

[davekippen]

What does "mashed medium high" mean? You may be at terminal gravity if you mashed high. It doesnt matter what yeast you use, or how much you use, if there is no more fermentable sugar for them to eat.

 

[Toga]

If you pitched 2 packs of 05 in a 3.5 gallon batch you pitched one pack to many. One pack would have been more than enough. It has only been 5 days. Let it ride. Also check to make sure it is fermenting between 59 and 75 degrees. It will ferment at a lower temp (I have gone as low as 52) but will take forever to finish.

 

[BigFloyd]

I know, but I just want to get this beer done ASAP,

That's pretty evident.

If you pitched 2 packs of 05 in a 3.5 gallon batch you pitched one pack to many. One pack would have been more than enough. It has only been 5 days. Let it ride. Also check to make sure it is fermenting between 59 and 75 degrees. It will ferment at a lower temp (I have gone as low as 52) but will take forever to finish.

+1.

I wouldn't pitch any more yeast into this batch. I don't believe that your US-05 "failed".

If you run this through Mr. Malty, a single 11g pack of US-05 gives sufficient cells for 5.25 gallons of wort up to 1.060. Did you rehydrate the dry yeast? Doing so (in 95-105*F sterilized tap water) will give you as much as twice the number of cells that survive intro into the wort.

If you dropped from 1.071 to 1.024 in 5 days, obviously you had a pretty good active fermentation going on. You're already at 5% ABV. Maybe you should consider leaving it in peace for 2 more weeks in the mid-60's and then check your gravity.

 

[goodgodilovebeer]

BigFloyd is right.
Dry yeast needs to be properly rehydrated to get the appropriate cell count. Yes, it'll work by doing it the easy way (sprinkling it on top of the wort), but a ferment with rehydrated dry yeast is every bit as good as a Wyeast or White Labs liquid culture. The only difference will be the yeasts "personality". Depending on what the temperature of the ferment was, try warming it up a couple of degrees and re-suspend the yeast (swirl, NOT shake). Chances are, the gravity will drop some more. Mash temp may be the issue as well; Med-High is kind of vague, are you talking 158f or 168f?

 

[VictoryAle]

Thanks for the replies guys,
When I say medium high, I mean 69c. I know for most peoples systems that would be considered straight up too high, but having used 1056 several times before if I mash at 69c I get the 75-80% attenuation that I desire, at least. In stating "medium high" I meant to indicate I was going for a relatively average performance from a yeast with a rep for being a beast.

I always let my IPA's sit in primary for at least 2 weeks, and have never before assumed completion of fermentation in less than 10 days -I know I seem impatient, but it's just that I don't want this beer to sit around while nothing is happening. My worries of it having failed came from my research of several folks saying they have noted weird/inconsistent performance from us 05 (as I have), and this is my first time using it. I suppose I am learning different yeasts can act very differently, and even one particular strain of yeast can act very differently, depending on variables..
I will sit tight and take another reading in a few days. I just figured I'd see at least a point or two difference in gravity in two days, not even a week after pitching.

 

[VictoryAle]

Also, regarding Mr Malty's dry yeast calculator,
The yeast pitching calculator over at brewer's friend says that mr malty estimates 20 billion cells per gram of dry yeast whereas danstart and fermentis claim a much lower number of 5-6 billion, and they also reference a study claiming 8 billions cells. Brewer's friend themselves set their calculator to 10 billion cells; According to that number the calculator told me to use two packets.