Wyeast Activator - 1.072 OG...1 pack...

[dospacificos]

First time using a liquid yeast yesterday and used a single wyeast activator smack pack per LHBS instructions for my 1.072 OG ale, but 15 hrs later I'm only getting about 1 bubble every 15 seconds. Looked around here to see if I should be concerned, and it looks like for that OG i should have used two packs or made a starter.

So what now, should I go back to my LHBS, buy another pack, and add more yeast? Are there any issues with introducing new yeast 24 hours after pitching the first?

 

[kh54s10]

IMO, it wouldn't hurt to add another pack of yeast, but since the yeast are already reproducing to cell counts to ferment your beer you would be wasting the $.

Your beer is already fermenting since you are getting off gassing. It may have some off flavors due to underpitching. These flavors, probably, will not be enough to make a big difference.

edit: Actually you should have pitched 2.7 packs. The lag time will be longer since the yeast will first have to reproduce, then start their work fermenting your beer. I think you will be OK. I would not pitch more yeast. You will make good beer. Using starters or more yeast should make your good beer better.

mrmalty.com is a good source of information on yeast and starters.

 

[dospacificos]

Thank you. I would rather spend the extra $ if there's a decent chance it will improve the beer. Do you think adding more yeast would help even just a little bit?

 

[HollisBT]

I think that adding more yeast would definitely help. That is quite under pitched IMO, and while you do have signs of fermentation, those yeasts are going to be stressed and spit out some off flavors.

 

[homebeerbrewer]

Don't waste your money on more yeast at this point. As long as you aerated your wort, you should be fine. Don't go by airlock activity, it's not a fool proof way to know if you're fermenting. Let the yeast do their job for at least 2 weeks, then check your gravity.

 

[Quadrupled]

If it was me, I wouldn't worry about it; however, if it will put you at ease, I say go for it.

Take a look at the Mr. Malty website (http://www.mrmalty.com/pitching.php) for determining your future yeast pitching rate. You may see Revvy state that a Wyeast smack pack is only sufficient for an OG of 1.030 or less, which the Mr. Malty calculations support.

Best of luck.


Mr. Malty says: "The general consensus on pitching rates is that you want to pitch around 1 million cells of viable yeast, for every milliliter of wort, for every degree plato. A little less for an ale, a little more for a lager. George Fix states about 1.5 million for a lager and 0.75 million for an ale in his book, An Analysis of Brewing Techniques. Other literature cites a slightly higher amount. I'm going with Fix's numbers and that is what the pitching calculator uses.

The Math

If you're curious, here is the simple math to calculate the number of cells needed. For an ale, you want to pitch around 0.75 million cells of viable yeast (0.75 million for an ale, 1.5 million for a lager), for every milliliter of wort, for every degree plato.

(0.75 million) X (milliliters of wort) X (degrees Plato of the wort)

There is about 3785 milliliters in a gallon. There are about 20,000 milliliters in 5.25 gallons
A degree Plato is about 1.004 of original gravity. Just divide the OG by 4 to get Plato (e.g., 1.048 is 12 degrees Plato).


So, for a 1.048 wort pitching into 5.25 gallons you need about 180 billion cells.

(750,000) X (20,000) X (12) = 180,000,000,000

As an easy to remember rough estimate, you need about 15 billion cells for each degree Plato or about 4 billion cells for each point of OG when pitching into a little over 5 gallons of wort. If you want a quick way of doing a back of the envelope estimate, that is really close to 0.75 billion cells for each point of gravity per gallon of wort. Double that to 1.5 billion for a lager."

 

[beerman0001]

Waste of money fermentation has already started.