Using an old packet of dry yest to kickstart fermentation

[jmd1971]

Hi, after brewing an altbier on Sat & pitching Wyeast 2565 (Kolsch), I had no activity after ~36 hrs. To clarify, when I activated the smack pack, it never really inflated so I suspected something was off. However, as I was in a pinch I went ahead & pitched it anyway. The wort was on the cool side when I pitched - probably high 50's but then rose into the low. 60's in the ambient temps in my basement which is right in the suggested range of 55-70. After 24 hrs of no activity, I moved upstairs into the high 60's to try to kickstart but no dice.

Now, as I still had no activity & had no other fresh yeast on hand, I dug through the fridge & came up with an old pack of US-05. It wad a 2009 Best By date on it but I didn't have many options so I pitched last night.

After about 6 hrs now, I have activity - but I am wondering if Im looking at any off effects from using this old yeast? Any thoughts or ideas?

Thanks!

 

[boist]

Try warming the wort to about 68-70 and giving it a good shake. If there's yeast alive in there it might be dormant, so this could help.

In the future, use a starter. Not only will it help you achieve proper pitching rate, it will also help you make sure your yeast is alive and viable. In this case, after your initial problem, I would have also made a starter for the dry yeast. It's not commonly done, but since the yeast was old it would have helped insure viability.

 

[jmd1971]

Thanks - yeah, I had already raised to 68-70 & swirled twice with no luck. I know starter are recommended & used to do them a few years back, but I'm too lazy so have been just pitching right from the smack pack. I guess it would've helped in this case.

There is activity now after pitching the dry yeast - I'm more curious if there are any flavor, etc concerns from using the old yeast?

 

[boist]

Well... Old yeast is distressed yeast. Stress is never good, as stressed yeast can produce a whole variety of off-flavor compounds etc. That said, dry yeast that has been properly stored (in the fridge) could last for years with no real problem. If you see fermentation starting in earnest you can go ahead and slowly lower the temp to about 65 (wouldn't go below that, that's about the lowest limit for 05) and just let it go. The cold temp will hopefully keep temperature-related esters to a minimum (you are trying for a very clean beer, after all), and as for stress-related compounds there's not much you can do, so I wouldn't worry. Chances are your beer will not be quite as clean as you'd hoped, but it'll probably be quite drinkable.

 

[jmd1971]

Thanks for the input - it's started fermenting steadily with 1/2 of krausen since about midnight. Like you said, there's not much I can do now. Maybe I should have waited until today & gotten a fresh smack pack.

Oh well - I guess we'll see in a month or so!

 

[beergolf]

I am guessing that after 6 hours an old pack of US-05 would not start that fast. The activity you are seeing is probably the Kolsch yeast finally kicking in and getting started. Either way you will be fine.