I was looking at a 1 gallon jug the other day (I ferment in them) and something grabbed my interest. I can really shake the bejesus out of them to oxygenate.
Some of the discussions that have evolved out of the “Shaken, Not Stirred” discussions involved the O2 demands of the majority of the brewer’s yeast available to homebrewers. Mark has stated a few times that most of these strains are Class O1 or O2 strains with respect to O2 demand (4-8 ppm).
I’m no super brain but it would seem to me that those of you using ~5 gal buckets and carboys would have a hell of a time shaking that vessel and getting the kind of foam I get shaking my 1 gallon jug. 5 gallons of water weighs about 40 lbs. and a carboy an additional 10 lbs. or so.
I guess my question is this: For those that shake or swirl the carboy/bucket, is it even possible for you, given the weight of the liquid and the vessel combined, to shake/swirl vigorously enough to reach saturation? Obviously a MixStir or Pure O2 will get you there no problem, and in the absence of a DO meter, this post is a moot point, but I couldn’t help but entertain the thought.
Probably not, especially given that the head space of the vessel is a key component to the method. 5 gallons in a 6.5 carboy would not have the necessary head space to get the proper foaming.
I usually ferment 5-5.5 gallons in a 6.5 gal carboy. While I have no idea how much oxygen ends up dissolved in the wort, I’m usually able to get the headspace very nearly full of foam.
I set the carboy on a rubber mat in my garage, then tip it over to about it’s balance point and shake back and forth vigorously. Usually I’ll do it for at minimum two minutes, sometime longer depending on how much my forearms are burning.
I have no idea how much DO I get either, but I take that 1 gallon jug and shake the hell out of it. It’s super light and I throw the cap on and have at it.
I’m fond of a good old balloon whisk. I can fill the headspace on a 7.9 gallon bucket from a 5 gallon batch of wort with foam and only a moderately sore elbow.
It’s definitely possible to get close (since you can only asymptotically approach saturation). It’s just a question of how long it takes. A bucket of wort sitting at ale pitching temperature will eventually reach 9 ppm DO. Shaking just accelerates the process. I get that the real question is whether you can endure enough shaking to get near that. This paper would suggest yes.
I run filtered air at 2.5 psi through a stone for 10 min and call it good.
Wyeast says that 40 seconds of splashing and shaking is enough. https://www.wyeastlab.com/hb_oxygenation.cfm. To me splashing and shaking is a lot less work than shake until turned into foam.
I just noticed that White Labs does not agree in its FAQ.
Before I had my aeration stone I would pour back and forth from my BK to fermenter several times till frothy and had great results from my fermentations. Not really an answer, just another (semi?)viable option?
I sit the better bottle on the edge of my chest freezer/fermenting chamber, and vigorously rock it back and forth for a minute or so. I also pitch a healthy starter at high krauesen. More than adequate for my sensibilities.
Not really looking for any answers for myself. It was more of a think out loud thing. I was just curious if the standard rocking back and forth method was adequate to achieve saturation.
It’s a rate thing rather than a quantity thing. By creating a large amount of foam you are maximizing surface area and allowing the O2 to diffuse in rapidly. Other methods will still get you there, but they will take a lot longer.
Ive heard so many method comparisons, pros and cons, and have tried them all but the fish pump. Ive settled with o2 injection and see no reason to ever change. The problem I see is that post boil the wort is depleated of o2. I dont have much faith in the headspace containing enough o2 to do the job. Splashing in open air might do it, but whats in the air? I just like my o2 wand. In my opinion its the surest and most sanitary method.
I have just recently gone back to the O2 wand after years of the mix stir. I like the limited exposure to the ambient air, especially during the warmer months - just don’t like the worry about airborne critters in my 10-12 gallon batches, either, Jim.