Homebrewers Association  AHA Forum
General Category => Yeast and Fermentation => Topic started by: roguejim on May 29, 2012, 11:25:29 PM

So I got my stir plates working. Time to use them. My yeast, unfortunately, isn't the freshest. The WY2206 is dated 42412. The WY2278 is dated 20112. (The yeast calculator indicates only 13% yeast cell viability in the WY2278!) Anyway, how long will a 1.5L starter take to ferment out before I step it up?

Took me about 10 days to step up 4yr old Farmhouse Ale yeast to 3.6L. Yours should be a piece of cake! :)

Check out the yeastcalc.com calculator. It will help you figure out the steps you need. I would say about 3236 per step

If your fermenting at room temp (72F), it should only take about 24 days to completely ferment the initial starter.

Just doublechecking the math... the rule of thumb is 25% viability loss per month (refrigerated), so the 2206 would be about 70%, and the 2278 about 35%. Not that it will make a huge difference in the sizes of the starters.

Can you just base it on time? Wouldn't temperature also be a factor?

Just doublechecking the math... the rule of thumb is 25% viability loss per month (refrigerated), so the 2206 would be about 70%, and the 2278 about 35%. Not that it will make a huge difference in the sizes of the starters.
I guess it depends on whose calculator one uses? This one ( http://www.yeastcalc.com/index.html ) indicates only 13% viability for the 2278. I've emailed Wyeast to see if this would be an accurate number, assuming the yeast has been properly stored by the LHBS. I pitched the 2278 into a 1.5L starter. Would one more step be adequate? How large would you make the next step?

Just doublechecking the math... the rule of thumb is 25% viability loss per month (refrigerated), so the 2206 would be about 70%, and the 2278 about 35%. Not that it will make a huge difference in the sizes of the starters.
I guess it depends on whose calculator one uses? This one ( http://www.yeastcalc.com/index.html ) indicates only 13% viability for the 2278. I've emailed Wyeast to see if this would be an accurate number, assuming the yeast has been properly stored by the LHBS. I pitched the 2278 into a 1.5L starter. Would one more step be adequate? How large would you make the next step?
I received a quick email from Jess at Wyeast. He states, "Jim,
It is really hard to estimate this number. I do not agree with the calculator's percentage numbers you are using (likely the Mr. Malty calculator). I donâ€™t like to give estimations because it is so variable and the only way to know this number is to actually analyze it. If you must plug in a number, I would use 75%, though I will not guarantee this is the actual viability.
Does that make sense?
Please let me know if you have questions."
Jess Caudill
Brewer/Microbiologist
Wyeast Laboratories, Inc.
P.O. Box 146
Odell, OR 97044 USA
Phone: 5413541335 Fax: 5413543449
jess@wyeastlab.com
www.wyeastlab.com

So, now I'm wondering what value an online yeast calculator has when it can estimate a yeasts viability at 13%, and the yeast lab guesstimates the viability closer to 75%. Talk about a disparity in numbers. So, who do you trust?

I'm confused why you need to know? Start it a few days in advance and let it ride. If it's done early put it in the fridge. Decant the morning of the brew and add a little more starter to give it a head start...

I'm confused why you need to know? Start it a few days in advance and let it ride. If it's done early put it in the fridge. Decant the morning of the brew and add a little more starter to give it a head start...
because when he pitches the yeast into 1.5 liters of starter wort he will end up with about twice the amount of viable yeast as he started with. so if he's only got a few billion cells and he needs 200 billion 1.5 liter single step isn't going to cut it, he will need at least a second step fermented out more or less completely to hit the population he wants. but if he's got 100 billion viable cells into 1.5 liters it will probably be sufficient to get his target population.

because when he pitches the yeast into 1.5 liters of starter wort he will end up with about twice the amount of viable yeast as he started with.
Probably not. If you start with 100B and end up with 200B, then starting with, say, 30B would probably result in more like 130B. Give or take some pretty enormous tolerances.

For me, the point now is how to determine the starting yeast cell count when the "experts" are so far apart in their numbers. If you don't know your starting point, the rest is somewhat of a crapshoot. I emailed Jamil about Jess's numbers. He responded that Jess is assuming perfect storage/handling when the yeast leave the lab, and is not considering the nutritional deficiency of the "smack pack" medium over several months. Jamil's numbers are based on empirical evidence from numerous smack pack/vials that he analyzed.

Unless you have the ability to count cells it's a very broad estimate anyway. I use the Mr. Malty/Yeast Calc viability estimate and build my starters off of that. My yeast storage conditions are generally consistent. If I don't like something about the fermentation profile of the beer I made using that size starter, the next time I make it I'll make it smaller or larger.

I think people get too caught up in yeast cell count. To me, if you have a 2L starter it does not matter how many cells you started off with you still have a 2L starter (as long as the yeast has finished). My guess is if you had a flask with a pack that was 75% viable and another flask with a pack that was 25% viable they will end up with approximately the same cell count. The 25% viable pack will just take a little longer. So why bother trying to figure out how many cells you have. Just figure out how many mL of starter you need for a given brew...

I think people get too caught up in yeast cell count. To me, if you have a 2L starter it does not matter how many cells you started off with you still have a 2L starter (as long as the yeast has finished). My guess is if you had a flask with a pack that was 75% viable and another flask with a pack that was 25% viable they will end up with approximately the same cell count. The 25% viable pack will just take a little longer. So why bother trying to figure out how many cells you have. Just figure out how many mL of starter you need for a given brew...
Really ??? Wow I just don't know where to begin trying to help you. I'll just say your guess would be way off. Oh and the size of your starter is only relevant to the number of viable cells you have. That's how you determine the size starter you need.

I think people get too caught up in yeast cell count. To me, if you have a 2L starter it does not matter how many cells you started off with you still have a 2L starter (as long as the yeast has finished). My guess is if you had a flask with a pack that was 75% viable and another flask with a pack that was 25% viable they will end up with approximately the same cell count. The 25% viable pack will just take a little longer. So why bother trying to figure out how many cells you have. Just figure out how many mL of starter you need for a given brew...
Really ??? Wow I just don't know where to begin trying to help you. I'll just say your guess would be way off. Oh and the size of your starter is only relevant to the number of viable cells you have. That's how you determine the size starter you need.
...which just begs the question...How do you determine your initial cell count if your yeast smack/vial is not fresh. I'm still in contact with Jess at Wyeast on this issue. If folks here are interested, I'll post his advice. We already know Jamil's.

Here's White Labs advice, btw Jamil co wrote a book with Chris White. I can't believe you have a guy from wyeast claiming 75% viable after almost 120 days.


What is the shelf life of White Labs Yeast?
Quick Answer: 4 Months
Long Answer: Yeast is a living organism. As such, it needs to be in the right conditions to survive. Dry yeast can stay alive for one year, but yeast left in liquid form, even though it's a better product in terms of taste and performance, is more perishable. At White Labs, we are constantly working on our recipe to maximize the viability of the yeast in long term storage. The longer we can make the yeast last in the vial, the better shape it will be in for fermentation. After 30 days in the vial, the viability of our yeast is 7585%, which is very high for liquid yeast. Yeast that is harvested after a brewery fermentation will typically have a viability of less then 50% after 30 days. Our high viability is due to the health of the yeast and nutrient content of our liquid at packaging. After 6 weeks, lag time before active fermentation is usually between 1520 hours. The shelf life for White Labs Yeast is four months. Yeast used after this point is usually fine, but lag times will be longer. There will be living yeast in most vials for 612 months, so if a starter is made to activate the yeast, successful fermentations can be carried out with aged yeast.

A. I don't need help.
B. I posted this elsewhere. I just started up a Wyeast Farmhouse Ale that was almost 4 years old. How viable do you think that was? I started on a stir plate with 500 ml of 1.040 starter. It took 56 days to eat up all the sugar. I then stepped up to 1.6L. it took another 45 days. I then cooled for 2 days, decanted and added another 2L two days before pitch. It was just about done when I pitched into 15 gallons. That's 3.6L/15 gallons of 1.050 beer. It was rocking within 2 hours and was just about done in 45 days!
Like I said, who gives a crap about yeast count. It only takes 1 cell to go thru 2 liters worth of starter. When it's done, you have a boatload of viable cells that will make any beer taste great!

A. I'm sorry to hear that
B. Not very viable and possibly useless, irrelevant post.
C. Completely and entirely false

It only takes 1 cell to go thru 2 liters worth of starter. When it's done, you have a boatload of viable cells that will make any beer taste great!
Well, that's not true. But in practice if you are doing stepped starters, you may not see as much of a difference with low or high viability yeast. Even with a stirplate, there's a maximum number of divisions you'll get before the yeast switch over to fermentation and/or crap out. One cell won't grow in 2L of wort, for multiple reasons, but if you start small you should be able to step up any amount of yeast. Starting from a plated culture, you can begin with 50ml or so.

OK, maybe 2 cells... ;D