Underpitched starter

[bhaff]

I apologize if this thread is already out there I couldn't find it easily on my phone.

Tonight I made two starters for brew day on the 16th. First starter is 3/4 cup dme and 650 ml and the second starter is 1.5 cup dme in 1300 ml. I am planning to decant the 1300 to build up for a big RIS. Anyways, I am using the same yeast for both beers 1056 and I split the swollen pack between the two starters. I originally planned to use half the dme since half the yeast would be used. I know I under pitched into my starter but am I screwed? I left both starters in my fridge at 50ish. Should I start over, man up, and get new yeast?

 

[dezman]

Well for the RIS I would probably get some more yeast. Whats the OG? Also whats the other brew? You might have been better off getting two packs and building starters from each pack. You could however build each up to the proper amount by stepping them up. I use this for starter step ups YeastCalc Yeast Calculator Splitting the pack is kind of a wild card though since your starting cell count for each could be diffrent. Just make sure you get enough for that RIS and you should be ok.

 

[bhaff]

RIS should be 1.108 and the porter 1.064. I was planning to decant the yeast for the stout once or twice to build it up. It just made sense at the lhbs today. Think I need to leave it in the cool fridge?

 

[ChadChaney]

I second that, I have split smak-paks before, since I only had 2 one liter flasks, with pretty good results. Search this site or Google how to step up a starter and you should be fine. Another option, although not as good, is to pitch more yeast towards the end of the vigorous primary fermentation. I did this with a RIS not to long ago, made a calculation error, after a few to many brews, and was short of my FG. I added a re-hydrated pack of Notty and hit the FG just fine. I am bulk aging this brew, so I am not worried about bottling/kegging before the fermentation is all the way finished. I went form 1.030 to 1.020 in about 5 days with NO visible signs of activity.

 

[dezman]

I would pitch the 1.3L starter into a gallon size starter for the RIS (use a milk jug). Then step up the 650mL starter into the emptied 1300mL . Assuming you have roughly half the cell count in each starter this should be enough for each beer. Hope this helps.

 

[wolverinebrewer]

Mr Malty says you need 379 billion cells for the RIS and 233 billion for the smaller beer. So, for the RIS alone use 2 smackpacks into a 3.5 liter starter or use 2 dry packs of US-05. What I would do is combine the original starter you made into one 2 liter starter and use that on the smaller beer and get 2 dry packs of 05 for the RIS. Problem solved. Of course, this is all dependant on the age of your yeast pack. If its old, you will need more.