Adjuncts in a Conical for Secondary

[Smitty4263]

I know that you can remove yeast from a conical and use it as a primary and a secondary but if I want to add adjuncts how do I avoid adding too much oxygen? I imagine just dropping in whatever fruit or coffee/chocolate would cause a splash.

 

[Jtvann]

I might be in the minority here, but I believe many home brewers tout that oxygen boogie man a little bit too hard. We seem to go to great extremes to keep the slightest sniff of 02 out of our beer. The majority of breweries I see just pull the cap off and dump in. I do that as well. I've got a NEIPA on tap right now that had 22 oz of hops and was brewed in late May. Theres no signs of oxidation or loss of flavor.

If you want to add one more extra layer, just bubble some CO2 in the bottom while the cap is off so that you have some sort of positive flow out.

I'd love for someone to tell me how to add 12 lbs of apricots without just uncapping and dumping.

 

[duncan.brown]

For dry hopping in my unitank, I use the trick being discussed here:

https://www.homebrewtalk.com/threads/stupid-question.684287/#post-8965901
That avoids oxygen and also this:



That would work for small amounts of adjuncts like cocoa nibs.

But yeah, I don't see how you'd do 12 lbs of fruit without it getting really annoying. I suspect that any oxygen in that case would be scavenged by the yeast as fermentation starts up again on the sugars, but I don't brew fruited beers so I don't know for sure.

 

[Vale71]

But yeah, I don't see how you'd do 12 lbs of fruit without it getting really annoying. I suspect that any oxygen in that case would be scavenged by the yeast as fermentation starts up again on the sugars, but I don't brew fruited beers so I don't know for sure.

Just a friendly reminder that fermentation is an anaerobic process and yet people keep mentioning it as an oxygen-scavenging process when it's clearly anything but. Any oxygen you introduce cold side will oxidize the beer, period.
As to the original question if it's not a huge amount you can use one of the gizmos that many homebrewers use to do oxygen-free dry hopping in their conicals, even pressure-capable ones. Here's one of several threads where this has been discussed:

https://www.homebrewtalk.com/threads/hop-dropper-for-ssb-unitank.680865/

 

[duncan.brown]

Just a friendly reminder that fermentation is an anaerobic process and yet people keep mentioning it as an oxygen-scavenging process when it's clearly anything but.

S. cereviesiae is a rather interesting organism as it uses fermentation even in the presence of oxygen when it could, in principle, respire aerobically. This presents an evolutionary curiosity because fermentation yields less ATP per molecule of glucose than aerobic respiration (by a factor of 6, which is significant). My understanding is that the evolutionary origin of such Crabtree-positive yeasts is a topic of debate in the community. If you understand why S. cereviesiae behaves this way, I’d love to hear.

However, your statement that yeast never uses oxygen during fermentation is not true. The short-term Crabtree effect, which is a sensing and metabolic pathway that S. cereviesiae has evolved, allows it to undergo immediate aerobic alcoholic fermentation in response to the provision of a pulse of excess sugar to sugar-limited yeast.

So I am not convinced that the metabolic processes induced in the yeast by the ingress of a small amount of oxygen when adding a lot of simple sugars from fruit to beer that has undergone most of its primary fermentation, and the subsequent effect of the oxygen on the beer (the OPs question), are as simple as you suggest.

I’m not making a sweeping statement that cold-side oxidation can be ignored. It’s true that letting oxygen get into green or finished beer is generally bad (but not always, e.g. Cask Conditioned Ale). I’ve also seen people claim that it’s ok to let oxygen into finished beer if there is still live yeast in there. With no little to no sugar, the yeast will ignore the oxygen and it will (eventually... it’s not an immediate reaction) oxide compounds in the beer introducing off flavors.

I suspect best thing for the OP is to experiment with dropping fruit using multiple dumps from a hop dropper vs just dumping it in without worrying too much about zero oxygen ingress and see which produces a beer that tastes best to them (vs the pain of adding 12 lbs of cherries in a hop dropper).

References for those interested in yeast physiology:

https://www.frontiersin.org/articles/10.3389/fmolb.2014.00017/full
https://onlinelibrary.wiley.com/doi/full/10.1002/yea.1430
https://pubmed.ncbi.nlm.nih.gov/25161062/

 

[duncan.brown]

I might be in the minority here, but I believe many home brewers tout that oxygen boogie man a little bit too hard. We seem to go to great extremes to keep the slightest sniff of 02 out of our beer. The majority of breweries I see just pull the cap off and dump in. I do that as well. I've got a NEIPA on tap right now that had 22 oz of hops and was brewed in late May. Theres no signs of oxidation or loss of flavor.

I think there's some truth in what you say. There's a nice article (with references) on oxidation posted on MoreBeer's web site here:

https://www.morebeer.com/articles/oxidation_in_beer
My take on oxidation (as with so many things in life) is "it depends." It depends on the amount of dissolved oxygen, when and how the oxygen is introduced, what other processes are happening in the beer, the time between oxygen ingress and consumption, the style of the beer, and the perceptions and preferences of the person drinking it.

I love it when I can tap a cask of ale to the air and enjoy it as the flavor evolves due to oxidation as I drink it over three days. (I generally only do this when I have friends over to help, as drinking 2.5 gallons in three days is ambitious even for me.) For a nice discussion on this, listen to the Craft Beer and Brewing podcast episode where they interview Stephen Kirby.

However, I go to great lengths to keep oxygen out of my Helles, except when oxygenating the cold wort right after yeast pitch. I just switched my old copper HERMS coil to stainless to reduce possible oxidation in my lagers.

I might even go LODO...

 

[Vale71]

However, your statement that yeast never uses oxygen during fermentation is not true. The short-term Crabtree effect, which is a sensing and metabolic pathway that S. cereviesiae has evolved, allows it to undergo immediate aerobic alcoholic fermentation in response to the provision of a pulse of excess sugar to sugar-limited yeast.

There is no such thing as aerobic alcoholic fermentation. Respiratory metabolism yiealds H2O+CO2 and no ethanol.

You misunderstood my point, sorry if I was too terse. What I mean is that it's wrong to link fermentation activity with O2 uptake as the two are not in any way related. As a matter of fact the highest O2 absorption by yeast takes place in the growth phase which takes place well before fermentation begins.

 

[duncan.brown]

What I mean is that it's wrong to link fermentation activity with O2 uptake as the two are not in any way related.

I think I may be confusing things by using the word "fermentation" to refer to two different things: the processes of turning wort into beer (probably what most home brewers mean) vs a metabolic pathway that happens in yeast (what a microbiologist would mean). I'm not a microbiologist, but I should be more careful.

I agree that fermentation defined as a metabolic pathway does not use oxygen to produce ATP. Saccharomyces cerevisiae can use oxygen to produce ATP, but that metabolic pathway (aerobic respiration) does not produce ethanol.

However, saccharomyces cerevisiae is neither an obligate anaerobe (does not grown in the presence of oxygen) nor is it a true facultative anaerobe (can grow either with or without oxygen) as it is unable to synthesize its cellular structures in anaerobios. So yeast does use oxygen during "fermentation," defined as the home-brewer sense, in the growth phase as you say.

Saccharomyces cerevisiae should prefer aerobic respiration when oxygen is present, as that is more energy efficient, but it can use fermentation to produce energy even when oxygen is present due to the Crabtree effect. The use of fermentation to produce ATP when oxygen is present is known as aerobic fermentation (i.e. fermentation in the presence of oxygen, but without the use of oxygen). Why some yeasts prefer the fermentation pathway when oxygen is available is not known for sure, although there's speculation that the alcohol produced by fermentation let the yeast out-compete bacteria for the sugars in fruit. How and when Saccharomyces cerevisiae switches between the two pathways seems to be non-trivial and a topic of active research.

To the OPs original point, it's not clear to me what the yeast will do if you add a load sugar from fruit. If they produce any new biomass, they will use oxygen. This is not typically an experiment that people have published results of, as far as I can see. Fermentation is obviously going to increase. Will there be any oxygen use by the yeast at that point in producing more biomass? Will the yeast use the oxygen introduced before that oxygen has chance to negatively affect the beer? Or will the Crabtree effect cause them to ignore the oxygen and just ferment the sugar? These seem like complicated questions which probably don't have a simple answer. Experiment is probably the only way that they can be answered.

However, if you're adding dry hops or cocoa nibs, yeah, keep the oxygen out.