Aerating wort

My technique has recently changed, in that I now brew all-grain and use a wort chiller (so much easier).

I've made two in the same manner, and on each the yeast took over 24 hours to show any signs of activity. They fermented fine after that, but I was wondering why they take so long. My only thought was that there wasn't enough O2 in the wort, should I just pop some holes in my filling pipe?

Thanks, and Cheers.

Ian

Aeration could be part of it, the amount of viable yeast pitched would effect it, and possibly temperature. For ten gallons I pitch a large starter and ferment my ales at 65f. I use an aerator at the end of the filling tube and fermentation activity shows within 6-8hours.
mark
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I think an extended lag time has more to do with under pitching than aeration.

I was talking to another brewer that I've known from a brew club back in the early 90's and how it's all about simplicity these days. One subject was aeration and how he gave up using O2. He now calls the trip out of the tube and hitting the bottom of the carboy aeration.

when I aerate with pure O2 I get longer lag times. yeast WILL consume the Oxygen first, and then begin fermentation.

when fermentation starts...wow is it fast and furious! beer still ferments in the proper time period (5-7 days).

Pure O2 and Yeast starters will help alot.

Have any of you who don't use oxygen ever had any off flavors? I've been having a little issue, and am trying to rule things out. I usually splash a lot during transfer, and shake the sh#t out of my carboy.

I have a nice method of simultaneously oxygenating and straining my wort before fermentation. While the boiling is going on, I throw out my spent grains from my lauter tun (two 7gal buckets, one has holes in the bottom). Then I wash the LT and sanitize it. Once the beer is chilled to pitching rate, I dump it through a double mesh strainer (sanitized in the boil) into the LT, and then run it out the spigot through a strainer bag (sanitized) attached to the top of the fermenter (I use plastic buckets). I figure after all these screens it passes through, it's quite well oxygenated. Also, once I run all the wort through, I usually aim to need another 1-2qts to top off to final volume, so I run this through the whole system to sparge the trub.

If you use carboys for primary fermentation, you could just attach the strainer bag to the top of the LT instead. Either way, you'll get a lot of wort dripping through the air which I assume is much better at oxygenating than just stirring with a spoon.

Question to Ian: Since you've gone all-grain, have you also started using liquid yeast? These are common upgrades people simultaneously make. However, a lot of people who do this AREN'T ready to make starters for their yeast, but this is essential to using liquid yeast.