wyeast smack pack questions

[wickman6]

I have read a lot about viability based on production date, but so far haven't found the answer I was looking for.

If an activated pack swells all the way, does that have any bearing on the cell count?

Let's say I have a year old smack pack I want to use. I know folks have used them before, reporting they may take as many as 10 days to fully swell. So, after that time, how many cells can I expect? Would it still be around 10% of a fresh pack?

Thanks!

Btw, I have tried Mr.malty but unless I'm missing something it still doesn't answer my question.

 

[theveganbrewer]

You're asking if new cells are produced when you activate it? Yes, but a very small number, the majority of the nutrient pack is nutrients, and I would assume that there is only a very minute amount of fermentable stuff just to get things going.

Try www.yeastcalc.com. You can type in the yeast manufacture date and it will show you how much is left. Then you can use the calculator on the bottom to figure out the yeast steps to get enough yeast for your recipe.

I think after a year you have 10% viability, so you'd have around 10 billion cells left, and maybe you wind up with 11 because of the nutrient pack. Remember, even if it doesn't swell, your list could very well still be alive, so give it a shot so long as you stored correctly.

 

[wickman6]

So, even if it swells all the way its still only 10% viable? It seems to me there would be a lot of reproduction since the nutrients provided are taylored to 100 billion cells. Wouldn't that mean those 10% have plenty to eat? Even if it takes them a week?

I'm very curious, I may send Wyeast an email just to see what they have to say.

I did check out yeastcalc, very useful tool. I prefer it to Mr.malty, for me its easier to use.

 

[duboman]

So, even if it swells all the way its still only 10% viable? It seems to me there would be a lot of reproduction since the nutrients provided are taylored to 100 billion cells. Wouldn't that mean those 10% have plenty to eat? Even if it takes them a week?

I'm very curious, I may send Wyeast an email just to see what they have to say.

I did check out yeastcalc, very useful tool. I prefer it to Mr.malty, for me its easier to use.

Viability decreases over time because the cells begin to die off. The nutrient pack is nothing more than a very small starter to get the cells active once the pack is broken but no where enough nutrient to grow the count back to 100%

 

[wickman6]

Viability decreases over time because the cells begin to die off. The nutrient pack is nothing more than a very small starter to get the cells active once the pack is broken but no where enough nutrient to grow the count back to 100%

Yes, I realize it will never grow back to 100 billion from what is in the pack. But how much will it grow is what I'm really after. Maybe double from the 10%? That would be around 20 billion cells. Just throwing a number out there.

I suppose its totally possible there's very little growth. I'd just like to find that out.

 

[KatCowMan]

Is this a time where a yeast starter could help get you to where you need to be? I recently started doing it, and for the first time did a double up with 2000ml starter because I had an older white labs California ale bottle jobby that i wanted to try and salvage. The first day it didn't seem to take off very well, but when I decanted the first spent wort and added the second the foam almost cleared the bottle, and it was just as good after I pitched into a 5 gallon batch in a 6 gallon carboy. I was almost afraid I was going to need to get a blow off tube setup.

 

[NordeastBrewer77]

Kat, any time you use liquid is a good time to make a starter. Anytime.

Wickman, make a starter according to the calc on MrMalty.com and you'll be good to go.

 

[theveganbrewer]

So, even if it swells all the way its still only 10% viable? It seems to me there would be a lot of reproduction since the nutrients provided are taylored to 100 billion cells. Wouldn't that mean those 10% have plenty to eat? Even if it takes them a week?

I'm very curious, I may send Wyeast an email just to see what they have to say.

I did check out yeastcalc, very useful tool. I prefer it to Mr.malty, for me its easier to use.

Check their website FAQ, it also says only a small amount of cells are created. The amount of ci2 needed to make the bag puff up is minimal and not a sign you've made a lot of new yeastm. You should call them to solve your curiosity but I'd really not worry about the numbers so much, a few billion cells here it there wwont make or break your beer. Everything is just an estimate.

 

[wickman6]

Check their website FAQ, it also says only a small amount of cells are created. The amount of ci2 needed to make the bag puff up is minimal and not a sign you've made a lot of new yeastm. You should call them to solve your curiosity but I'd really not worry about the numbers so much, a few billion cells here it there wwont make or break your beer. Everything is just an estimate.

Ok, great. Thanks, I must've missed that. I'll check it out.