5

The downside would be potential oxygenation of the beer, but "rousing" of yeast is a long-established practice. I'd suggest gentle swirling rather than shaking.


4

I would oxygenate (pure O2) right before or after the pitch. Just because the process has the chance to introduce bacteria or wild yeast and it's best if the yeast is there to become dominate before anything else. Aeration has much less risk, if just splashing or shaking the wort. I don't think this would matter much when it's done.


4

Oxygenating your wort using a tank is leaps and bounds more efficient (as well as more expensive) than agitation or splashing. Simply agitating or splashing your wort to oxygenate it will work for most average gravity beers (you're aiming for a minimum of eight parts per million of oxygen minimum), but will otherwise require a significant amount of effort ...


3

Honestly, this looks like a cut and paste and propbably doesn't differ much from thier other species of yeast that may benifiet from hard growth conditions. Yeast needs oxygen for healthy growth. Healthy growth reduces esters. If the yeast has a clean ester profile it will, do better with oxygen. All yeast grow better with oxygen, but some yeast you ...


3

It does not need to be 5.00000 gallons, don't worry about the small differences. You can aerate after pitching the yeast, so long as it's immediately after; the yeast need oxygen during the lag phase, but once alcohol starts being produced, you don't want to introduce oxygen at that point.


2

Too much oxygen in a starter is almost impossible, so long as you decant the liquid and don't pitch it with the yeast. If you plan to pitch the liquid (e.g. to kraeusen a beer or restart a stuck ferment) then don't stir at all since you'll be pitching oxidized wort. A vortex isn't necessary for oxygen uptake - just having the surface in continual motion ...


2

'Wouldn't the relatively cool temperature of the wort actually increase the solubility of the oxygen, and so reduce the need for vigorous mixing?' For sure. Looking at those revision notes, I think they are probably trying to emphasize that it's important, regardless of when oxygenation occurs, to provide some aid to the oxygen in dissolving; it's one of ...


2

I wasn't able to find a good spec sheet for that pump, but a comment somewhere said the outlet is 1/8" (and that is typical), so 1/4" tubing is quite a bit larger than you want. When aerating wort, you shouldn't really be needing much pressure, giving you some room for creativity when making this connection. You'll just need something better connection ...


2

It's important to note that they specifically say aeration is only unnecessary for 'first use'. This is very common for active dry yeasts, the reason being that most are grown under 'oxidative' conditions. As Denny Conn correctly points out, the point of aeration is to provide yeast the means of synthesizing sterols and unsaturated fatty acids, which allow ...


2

There is almost never a need to aerate/oxygenate with dry yeast. The purpose if aeration is that the O2 is used by the yeast to synthesize sterols. Those keep the cell walls flexible to encourage budding. Because there are so many cells in a pack of dry yeast, there is little to need need for cell growth.


1

1) Does aerobic fermentation has a place in this? If so, when and how, and where does the oxygen come from? Aerobic metabolism is a more efficient pathway to convert the glucose to cellular energy and therefore is always taken when O2 is present which is only during the initial phase. The time it takes until oxygen depletion occurs depends on population, ...


1

I recently started using O2 and temperature control, as well as turning my attention to brewing big beers (SG 1.100+). These big beers have come out clean, attenuated well, and were generally much better than previous attempts to brew even moderate beers around SG 1.070.


1

I used to use one, but I found it a hassle to use compared to my MixStir aerator. In addition, I found the Mixstir to work as well as any other method and it's considerably less expensive.


1

I don't think there's any need to aerate the subsequent batches. Think about the purpose of aeration...the yeast use the oxygen to synthesize sterols which keep cell walls flexible for budding. But the more yeast you pitch, the less need there is for aeration since you have adequate amounts of yeast already. In your case, by the time you add the second ...


1

Aeration/oxygenation is key. Without it yeast cannot grow successfully, which is basically the whole idea of batch fermentation (read: brewing). So, as you suspect, you really do need to do it. The best answer to this question depends on some missing information, specifically: what kind of yeast (liquid, dry, from a starter or previous batch) you're using; ...


1

I've conducted the mash and boil in one place and transported prior to fermentation in the past, with no issue. Yes, the drive will aerate some...but you will certainly need to aerate more prior to pitching your yeast, if you want to increase the chances of a healthy fermentation and less off-flavors. I would strongly suggest the small investment in a ...


1

I don't think there is a "better" here. Certainly the drive will help aerate, but I wouldn't rely on it. Shake the fermenter well before pitching.  On the other hand, jostling the already pitched wort shouldn't hurt unless you do so after fermentation starts to wane. At that point, aerating might cause introduce oxygen that the yeast won't clean up (and ...


1

I just realized that after fermentation is done, I will need at least an extra keg to transfer my beer out of the fermentors, anyway. My batches are of 3 kegs. So I will need to take an 4º keg to transfer the first. After that, I could just drain and clean the emptys one by one and do the other transfers. So what I've done was to fill the 3 kegs with ...


1

I think you could skip the CO2 & shaking in step 2: The bike pump should be able to make more than enough pressure to seat the seals, especially if they are well lubricated. The only question is whether air will go in fast enough. So maybe use a mountain bike pump, not not a road bike pump. The bubbles from the pump will do a more than adequate job of ...


1

Last time I heard someone tried to use an aquarium pump and a 2 micron stone it was a failure: the pump wasn't powerful enough. With a proper pump 30 min is said to be enough. However, there was Beersmith podcast where some guys from Maltose Falcon club made a split batch with a few different aeration techniques, and aquarium pump rated below pure oxygen (...


1

The other contributor to Acetaldehyde in beer is excessive aging on yeast. As the yeast cells stress, and eventually die, they can lyse (burst) and release AA from the cell interior into the beer. This happens a lot with big, high alcohol beers, because often they have trouble getting to the end fermentation, so the brewers prolong the fermentation time on ...


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