I brew big beers, usually 18 to 23 pounds grain and 8 to 10% ABV using dry yeast only. Have been reading about aerating big beer wort to give the yeast enough oxygen but does this apply to dry yeast?
From the Danstar FAQ:
Quote:
I always aerate my wort when using liquid yeast. Do I need to aerate the wort before pitching dry yeast?
No, there is no need to aerate the wort but it does not harm the yeast either. During its aerobic production, dry yeast accumulates sufficient amounts of unsaturated fatty acids and sterols to produce enough biomass in the first stage of fermentation. The only reason to aerate the wort when using wet yeast is to provide the yeast with oxygen so that it can produce sterols and unsaturated fatty acids which are important parts of the cell membrane and therefore essential for biomass production.
If the slurry from dry yeast fermentation is re-pitched from one batch of beer to another, the wort has to be aerated as with any liquid yeast.
Does the above apply to big beers or is it better to aerate? I typically hold drain tube from cooled wort in brew pot well above the wort level in the fermenting bucket. Is further aerating necessary for big beers? If so, how to aerate? An aquarium pump for a 5 gal tank and a small stone cost $10. Devises that use oxygen cylinders are faster and provide more oxygen but they cost $40 and more. If you aerate what do you use. Can a small fuel filter be used to trap impurities from the air?
Aeration of wort does help dry yeast. There are a myriad of ways to aerate the wort with air. Certain studies have indicated that shaking a carboy to swirl the contents is best, but I’ve also heard that criticism of the studies. I do this and while racking to primary I aerate the wort by running the wort down the side of the carboy so that the wort fans out (old winemaking trick). I also like to do open fermentations for big beers.
I use a handheld electric kitchen mixer. Sanitize the beaters and put it on high for a couple of minutes or until there is a large frothy foam almost overflowing from the fermenting bucket. This seems to work well for me for aerating and mixing the yeast thoroughly with the wort.
I think $40 is a cheap investment for the amount of benefit pure O2 gives the yeast. I’ve seen my lag time decrease by more than half over shaking/stirring/splashing. Especially for higher gravity beers and lagers, proper oxygenation is crucial for a clean and complete fermentation.
Its also much more sanitary than splashing around your unfermented wort.
Thirsty_Monk, interesting gadget but how do you use it? I assume the threaded ends fit inline when draining wort from pot to fermenter but what do you attach to the barb to aerate with, bottled oxygen, an aquarium pump, what?
Yes the threaded ends are liquid in and out and barb end is the gas injection in. You could use O2 but I just use air with sterile filter. There are different sizes of venturi tubes.
I almost exclusively use dry yeast. There is a definite affect when aerating the wort. It appears to be a shorter lag-time. But, one is just as well off by using splashing as a method of aerating and using dry yeast; it is much more important to properly rehydrate the yeast than inducing oxygen into the wort.
When “aerating” I prefer to use a cheap powder coated paint stirrer and my drill to whip up the wort. I’ve done with and without extensively and am now investigating whether or not one needs to aerate with dry lager yeast.
I ferment 3-gallon batches in plastic fermenters (5-gal better bottles and homemade fermenters made from food-safe buckets) and my last step in the brewing process is to put the fermenter on a folded towel, sit on the kitchen kickstool, and vigorously rock the bucket for no less than 5 minutes. My beers always have good “kickoff” and it’s good for my upper arms.
