Big beers and the need to double pitch?

So lets say you are brewing a big beeer like an Imperial Stout. I have two vials of white labs yeast in the fridge that came with the kit. I have since aquired all the equipment to do a starter.

If i make a starter with one vail of yeast is there still be a need to pitch the second vail or can I save it for a future brew? Will pitching the second vail help the fermentation?

Thanks for the input!

Austin

The amount of yeast you need to pitch depends on the starting gravity of the beer and the age of the liquid yeast. If the yeast is fresh and the gravity is low you will only need one vial. If the yeast is old and the gravity is high you might need to use both vials in the starter. What is the best by date on the vial and what is the starting gravity of the beer. With that information we can help you determine what you need to do

At work in a training class right now but I will get the date off of the vails when I get home tonight.

schweaty said:

The amount of yeast you need to pitch depends on the starting gravity of the beer and the age of the liquid yeast. If the yeast is fresh and the gravity is low you will only need one vial. If the yeast is old and the gravity is high you might need to use both vials in the starter. What is the best by date on the vial and what is the starting gravity of the beer. With that information we can help you determine what you need to do

Click to expand...

Date on the vail is March 30 2010

So starter with both vials or one vail and just pitch the second?

Depends on what the starting gravity is but I think you're going to need to use both vials. Use this calculator, it is a great tool.

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

If you make a big starter then you don't need the second vial. yeast is yeast, whether they come from a vial or a starter jug. I would go about 2 quarts of starter for this brew. you want your starter to be fermenting at full steam when you pitch it also.

Being that the yeast is 3 months old the viability has dropped significantly. I'm guessing (without knowing your starting gravity) that since its a RIS and they are usually 1.075+ that you're going to need both vials for the starter.

I made a 1.081 OG Scottish Ale a week or so ago. Using the Mr. Malty calculator, I pitched 1 vial of WLP028 into a 4.3 liter starter or so. Pretty big starter, but I only needed the one vial. I could've made a smaller starter if I used a second vial of yeast, but if you do that you should throw both vials into the starter.

FYI, I let the starter chill in the fridge after fermenting a day and a half or so to knock out as much yeast as possible. Decanted the 4.3 liters of malt liquor and pitched the entire slurry. My lag time was 5 hours, probably less, and the beer landed at 1.015 FG. I can't detect any esters as of now.

EDIT: My yeast was a little less than a month old.