yeast- no fermentation

[dafbach]

Hi all.

Two day ago I made an oatmeal stout into which I put in Wyeast Irish Ale smack pack. I have used these before with no problems.

On this occasion I was a little late taking the yeast out if the fridge and hence wasn't left at 20C for the full 3 hours. The pack had began to bulge slightly.

Roll on 50 hours and there is no fermentation, I checked this with a hydrometer. I probably pitched too early.

So I have a Safale S04 which I am going to add. My question is do I oxygenate the wort at this stage by stirring it up and risk infection, or pitch the S04 onto the wort with minimal disruption.

Thanks in advance

Daf

 

[peebee]

Perhaps you have "shocked" the yeast, so what's left may be taking its time building up numbers again. You may not see signs of fermentation while the yeast "grows" but it will use up any available oxygen while doing so. There's always the chance you've left yourself with an unviable population of yeast? So for piece of mind the packet of S-04 is not a bad idea. If there was some yeast in your original pitch it will have scavenged available oxygen, but the packeted dry yeast is prepared for an unoxygenated environment so you don't really need further oxygenation (provided you're not brewing something too strong - i.e. above SG1.050-or-55-ish - in which case you should have prepared a yeast starter in the first place). A rousing (a less than enthusiastic oxygenation) might help, might even kick the original yeast into action.

 

[dafbach]

Perhaps you have "shocked" the yeast, so what's left may be taking its time building up numbers again. You may not see signs of fermentation while the yeast "grows" but it will use up any available oxygen while doing so. There's always the chance you've left yourself with an unviable population of yeast? So for piece of mind the packet of S-04 is not a bad idea. If there was some yeast in your original pitch it will have scavenged available oxygen, but the packeted dry yeast is prepared for an unoxygenated environment so you don't really need further oxygenation (provided you're not brewing something too strong - i.e. above SG1.050-or-55-ish - in which case you should have prepared a yeast starter in the first place). A rousing (a less than enthusiastic oxygenation) might help, might even kick the original yeast into action.

Thank you for the reply. S-04 added with slight rousing, wort smells delicious and certainly sweet enough for conversion. Fingers crossed.

 

[foxbat]

Well, you've added the extra dry yeast now so that'll do it, but what was the date on the smack pack? My guess is that you may have underpitched. In this brulosophy underpitch experiment they had to wait 3 days for activity to show on an intentionally underpitched batch. The beer was fine though, as it almost always is.

 

[dafbach]

Well, you've added the extra dry yeast now so that'll do it, but what was the date on the smack pack? My guess is that you may have underpitched. In this brulosophy underpitch experiment they had to wait 3 days for activity to show on an intentionally underpitched batch. The beer was fine though, as it almost always is.

The date was nearing the 6 months, manufactured in March 18. The S04 has done the trick, we have airlock activity!

 

[peebee]

The date was nearing the 6 months, manufactured in March 18. The S04 has done the trick, we have airlock activity!

6 months? Almost certainly needed a starter, but you disadvantaged it instead by giving it a bit of a thermal "shock". Good to know all is well know.

I had some WLP002 recently which I had to delay brewing by a day for because the starter wasn't ready - and that was only 4-5 months past its manufacture date.