Is more yeast needed?

[jkdoubleu84]

I was wondering if you could provide some advice regarding my currently fermenting Imperial Stout homebrew. The OG for the beer was 1.090 and I pitched 1 vial of White Labs super high gravity yeast. It has been fermenting nearly 5 days (began 11/29 evening) and it appears to be fermenting slowly. I haven't done a gravity check (will do that tomorrow) but there is very little activity in the airlock. Based on this and a lot of information I have read, I think that I have underpitched. If that is the case, what are my options to get the necessary yeast level and to reach a reasonable FG around 1.020?

Thanks

 

[Dos_Locos_Brewery]

1. Pitch more yeast
2. Add Fermaid yeast nutrient
3. Add O2

 

[TipsyDragon]

your most likely ok. fermentation will slow as the yeast eat more and more of the sugars. beer typically takes 2 weeks to completely ferment out so your about half way through. an airlock is NOT a fermentation indicator its a pressure release valve. just because the bubbles slow or stop doesn't mean fermentation is over. don't do anything till you have several consecutive gravity readings of the same value that is significantly above your target FG.

oh and don't add O2 after fermentation gets underway. you will just end up oxidizing your brew.

 

[Doc Robinson]

With that OG, you should have pitched at least 300B cells, or 1 vial in a 5.25 liter starter. You are way under-pitched. My guess is that your gravity reading will be well above your target. I have never dealt with this issue because I always calculate the proper pitch volume when I brew, but do a search for stalled fermentation or adding additional yeast to figure out how to best go about it. Champagne yeast is ringing a bell somewhere, but I just don't know. From now on, go here to calculate your pitching rate:

http://www.mrmalty.com/calc/calc.html

 

[TipsyDragon]

you don't NEED to pitch that much but it is a very good idea. i've always just pitched 1 vial and been just fine. the 300B cells is the number of cells needed to start an active fermentation. 1 vial of yeast will build to that number by it's self it will just take longer than if you just started with that number to begin with. by this point you are already at that population or higher and are no longer under pitched.

 

[Doc Robinson]

you don't NEED to pitch that much but it is a very good idea. i've always just pitched 1 vial and been just fine. the 300B cells is the number of cells needed to start an active fermentation. 1 vial of yeast will build to that number by it's self it will just take longer than if you just started with that number to begin with. by this point you are already at that population or higher and are no longer under pitched.

NEED? Maybe not based on your point. Do you NEED heat in the winter in Indiana? No...wear a ton of layers. Is it nice? Yes. Pitch more yeast, make a starter, don't be lazy.

 

[jkdoubleu84]

Thanks for the input. Since I was already well into the fermentation when I first posted, I left it and after two weeks, the gravity is about 1.022. I am going to rack it to the secondary this evening. Next time I will make a starter.