Using old yeast

[jtbrewcrafter]

I decided to brew this weekend and picked up some oldish yeast from the lhbs. Its wlp023 - Burton Ale. Dated best by 1/1/15, so I figure that puts my mfg date at 9/1/14. When I plug this into the yeast calculator, it states viability 0.00%. Is this right? What now? Buy more yeast? Just pitched into 1.75 liter starter. Am I being too optimistic?

 

[HumulusHead]

I get 10% via mr malty. I'd bet you could get it going, may take longer than normal and maybe need to step it up again, but it might just be ok.

 

[jtbrewcrafter]

Yeah. I just checked MrMalty too with the same result. Glad Im starting early. Thanks for the reply.

 

[stpug]

At ~5% viability loss per month, you should be looking at about 75% viability. This is the rule I use myself. I do not trust those calculators for viability.

If you want to pick one to use then try HomeBrewDad's calculator:
http://www.homebrewdad.com/yeast_calculator.php

...and you're still looking at about 25%

 

[madscientist451]

I've used WL yeast that's 2 years past the expiration date. Hard to get started, but still alive. Since you're doing a starter you'll be able to see for yourself how its doing.

 

[BigFloyd]

Since you're doing a starter you'll be able to see for yourself how its doing.

This^^^^^.

 

[MagicMatt]

This^^^^^.

Could you elaborate a bit? What are some ways to check a starter to see how active the yeast is?


I ask because I'm in the same boat as the OP. I brewed yesterday and didn't see the MFG date of 10/1/14 until I went to create a starter. Using Beersmith, it told me that with my 1L starter (4oz DME) on a stir-plate I should expect about 160 billion cells. It was on the stir-plate for 24 hours prior to pitching. However it's now 26 hours since pitching into my wort and not a peep from the yeast.

I've since used both Mr.Malty and Brewer's Friend for yeast/starter calculations, and both show a much lower expected cell count (around 50-70 billion) with the size starter I used. Even still, I've never gone longer than 24 hours without seeing some kind of activity. But I've got nothing, nadda.

On a side note, these calculators do seem a bit untrustworthy, as when I put the MFG date of 10/1/14, I get a "0%" viability. But if I up the date to 10/10/14, I get 4%. Going to 10/31/14 gives 15%. I find it difficult to believe that going from 4 months to 5 months would go from 15% to 0%.

 

[stpug]

Could you elaborate a bit? What are some ways to check a starter to see how active the yeast is?


I ask because I'm in the same boat as the OP. I brewed yesterday and didn't see the MFG date of 10/1/14 until I went to create a starter. Using Beersmith, it told me that with my 1L starter (4oz DME) on a stir-plate I should expect about 160 billion cells. It was on the stir-plate for 24 hours prior to pitching. However it's now 26 hours since pitching into my wort and not a peep from the yeast.

I've since used both Mr.Malty and Brewer's Friend for yeast/starter calculations, and both show a much lower expected cell count (around 50-70 billion) with the size starter I used. Even still, I've never gone longer than 24 hours without seeing some kind of activity. But I've got nothing, nadda.

On a side note, these calculators do seem a bit untrustworthy, as when I put the MFG date of 10/1/14, I get a "0%" viability. But if I up the date to 10/10/14, I get 4%. Going to 10/31/14 gives 15%. I find it difficult to believe that going from 4 months to 5 months would go from 15% to 0%.

Wyeast MFG dates are supposed to give you a 6 month window of "product warranty" (whatever that means). I assume it means that the slap pack should "be good" and give "good results" within six months from that date. Wyeast uses a manufactured date (the "best by" date is six months later), whereas White Labs uses a "Best by" date (the MFG date for White Labs is considered 4 months prior).

If you're using Wyeast then you are well within the 6 month period of "product warranty" and should have good yeast - assuming the package was cared for (call it 80% viability and fairly good vitality). If you're using White Labs then you are 4 months out of the best by date (call it 8 months total; 60% viability with low vitality).

As far as starters go, if you simply put yeast in a container with low gravity wort for 24 hours and do nothing then you're essentially starting the fermentation of that wort (and proofing the yeast). You would likely see very little change of appearance in the starter wort, and potentially never see krausen. Pitching this into a batch of beer should give you the advantage that the yeast have had a chance to increase their vitality and build-up their energy reserves for later in the beer fermentation. HOWEVER, you would not have provided enough time for the yeast to multiply very much (if at all) so you would still be dealing with the original cell count (slightly more maybe) that came out of the slap pack.

If on the other hand you did a stirred starter with good aeration for 24 hours then you probably would have seen a change in the appearance of the starter wort - it generally gets "creamier"/"milkier" and even lighter. You might have or might have not see any krausen depending on various circumstances. If you saw a much creamier appearance in the starter wort then that would be an indication of yeast propagation (i.e. yeast multiplying). The result would have been a much larger cell count pitching rate to your beer and (theoretically) a better fermentation.

As I said above, I don't trust yeast calculator viability percentages. They seem overly "enthusiastic" when it comes to how quickly the yeast die. I like the 5% per month rule, followed by the fact that some yeast will survive for years in fridge environments (not that you'd want to use this yeast after years ).

 

[MagicMatt]

Yeah I used Wyeast (1335) so I'm within the 6 months. I use a stir-plate, and it was on it for 24 hours. I wouldn't call it an extremely vigorous stir, but enough to create an air funnel reaching almost to the stirbar.

As for the look of the starter, the first couple of starters I made years ago did show some sort of change within the 24 hours. But I've had several starters since then that have had zero visible changes. This was one of those, where there was no foam, krausen, milkiness, etc. But since this hasn't ever been an issue in the past, I didn't worry about it.

I'm so frustrated by this. I hate when things don't work like they should. Now I need to make a special trip back to the LHBS to get some new yeast. I think I'll just get some US05 or Nottingham.

 

[BigFloyd]

On a couple of lager starters last year I was having doubts about the viability of the culture on the stir plate.

Here's what you can do to check:

Sanitize a piece of cling wrap with StarSan. Swirl the starter if not using a plate. Remove the foil from the mouth of the flask and secure the cling wrap tightly with a rubber band. Watch the wrap for the next few minutes to see if it starts to bulge. If it does, the yeast is working on the starter wort and kicking off CO2.

 

[Chadwick]

I say use it. Do a starter of course and be prepared to step it up more than once.

RDWHAHB

BTW, I've stepped up yeasts that calculators promised had 0% viability months ago. Sometimes it took a while to build them up, but I did manage to build them up and the beers they brewed were perfect.

 

[phyllobeddo]

I found some WLP001 in the fridge that's dated 2007. Wonder if it's totally gone?

 

[Chadwick]

I found some WLP001 in the fridge that's dated 2007. Wonder if it's totally gone?

Well, I wouldn't have high hopes. But if you got nothing better to do, why not try? I wouldn't count of what you resurrect being the "same" as it used to be. Think about the movies. It doesn't always work out real well...... If I've learned anything from horror movies it's this: Don't resurrect the dead, it ends in tears every time.

 

[phyllobeddo]

Well, I wouldn't have high hopes. But if you got nothing better to do, why not try? I wouldn't count of what you resurrect being the "same" as it used to be. Think about the movies. It doesn't always work out real well...... If I've learned anything from horror movies it's this: Don't resurrect the dead, it ends in tears every time.

When I get my stir plate built, I will give it a whirl to find out what happens.

 

[stpug]

Yeah I used Wyeast (1335) so I'm within the 6 months. I use a stir-plate, and it was on it for 24 hours. I wouldn't call it an extremely vigorous stir, but enough to create an air funnel reaching almost to the stirbar.

As for the look of the starter, the first couple of starters I made years ago did show some sort of change within the 24 hours. But I've had several starters since then that have had zero visible changes. This was one of those, where there was no foam, krausen, milkiness, etc. But since this hasn't ever been an issue in the past, I didn't worry about it.

I'm so frustrated by this. I hate when things don't work like they should. Now I need to make a special trip back to the LHBS to get some new yeast. I think I'll just get some US05 or Nottingham.

Sounds like a great stirring speed, IMO. I like the funnel to almost reach the stirbar myself. Some yeast just take longer to get going for various reasons (usually some form of neglect or long hibernation). When I make starters from refrigerated liquid yeast I like to give myself about 5 days lead time; 1 day to get going, 1-1.5 days to finish out, 2.5-3 days of crashing. That way if things take longer to get going or finish out, it comes out of the crashing time. I like, at minimum, 1 day to crash out for most strains, so there's almost 2 days of wiggle room in my process.

Regardless, I would not be concerned with your starter based on the details you've provided. The starter wort was good strength, the yeast were within a reasonable time frame, you gave them a decent time on the stir plate with good stirring. I suspect your beer will get going at any moment if it hasn't already. If you're using a bucket then and trying to judge activity by airlock bubbling then you may not be getting a representative picture of what's going on inside. You may want to crack the lid and have a peek, or put a flashlight on the lid so see if you can see the krausen line.

 

[MagicMatt]

I suspect your beer will get going at any moment if it hasn't already.

You called it. The GF texted me around 1pm today to tell me I was getting 1 bubble every 5 seconds (I have a 1" blow-off tube going into a quart of Starsan). By the time I got home, there was a nice krausen (I do use carboys, because I like to see what's going on inside!) and a steady bubble rate of about every 3 seconds. I guess it was just the age. I used this exact strain/MFG date 3 months ago without any issues.

When I make starters from refrigerated liquid yeast I like to give myself about 5 days lead time; 1 day to get going, 1-1.5 days to finish out, 2.5-3 days of crashing.

Just curious, how do you know when you're "finished" with the starter? I suppose you can check the gravity, right? But what you're targeting is a specific number of yeast cells, not gravity. I guess I never thought about it. I just always use Beersmith to tell me how big of a starter to make based on % viability, and then shoot for 24 hours. I don't decant or anything - maybe I need to start looking into that, and multi-step starters, etc.

 

[stpug]

Just curious, how do you know when you're "finished" with the starter? I suppose you can check the gravity, right? But what you're targeting is a specific number of yeast cells, not gravity. I guess I never thought about it. I just always use Beersmith to tell me how big of a starter to make based on % viability, and then shoot for 24 hours. I don't decant or anything - maybe I need to start looking into that, and multi-step starters, etc.

I will almost always see some form of krausen on my starters. Sometimes it's just a little froth floating around the middle of the flask, and other times is a thin 1/8" layer covering the entire surface. This is the key indicator that major activity is currently taking place. Usually, within 24 hours I will see that froth/layer disappear almost completely, which is an indicator that major activity has subsided - there may still be minor activity taking place but this is of less concern to me.

In addition to the krausen indicator, there is what I think of as the "creaminess factor". After first making my starter and mixing in my yeast, I describe the color and translucence to myself. My usual descriptions are something like: "slightly watery caramel", "light caramel, somewhat transluscent", "dark caramel, not creamy", stuff like that. That creates the baseline. Then I let the starter do it's thing and, as mentioned above, will usually have some form of krausen development to go off of. When the krausen has passed, I again try to describe the creaminess, and it usually comes out like: "milky and non transparent", "off white, creamy", and other descriptors like that. Sometimes, the strain of yeast is a highly flocculant variety and you can actually see the little globules floating around in there like milk that's starting to curdle a bit. Keep in mind I'm always using the lightest of extracts when doing starters (golden light, or pilsner extract) so the starting color is always in the light caramel spectrum.

There has been an instance or two where I did not note any significant krausen formation; maybe just a scant ring of bubble clinging to the glass around the surface of the starter, but even in these cases the creaminess of the starter went from the usual "watery light caramel" color to "milky, creamy, and off-whitish".

There have been instances where I've actually waited 3-4 days for a starter to just get going, and then another day to finish out (even the slowest starters will finish out in about a day). While these yeasts proved to be not very good beer fermenters, they DID propagate new cells and end up with a nice creaminess in the end.