In-line aeration and chiller re-circulation?

I'm trying to figure out the best way to aerate (doing 20g batches), and something in-line seems the most elegant; however, I was wondering if re-circulating chilled/aerated wort back into the hot kettle would pose some kind of problem.

Am I way off here?

I just chilled a batch by recirculating back into the kettle and it worked great. It's definitely a viable option.

Yeah, I've never done it so looking forward to a new process, but my concern is w/ the aerated wort being re-circulated. Is that a problem at all?

I wouldn't do this because you're substantially increasing your risk for an infection. Once you're below 180 or so the risk starts to go way up. Aerate it once it's cooled and on the way to the fermenter.

jcaudill said:

I wouldn't do this because you're substantially increasing your risk for an infection. Once you're below 180 or so the risk starts to go way up. Aerate it once it's cooled and on the way to the fermenter.

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How does aerating during chilling pose any more risk for bacteria than aerating after the wort is cooled?

I think it would be a great way to save time and effort.

Aeration does not pose a risk - recirculating cooled wort back into the kettle does.

I don't think there would be an increased risk of infection even with recirculating cooled wort back into the kettle. Be sure to, initially, recirculate hot/boiling wort through the pump and tubing. This will ensure everything is sterile. After that then start chilling and recirculating.

I mean this in the nicest way possible: I don't care how sterile you think this is. It's not. Once you get the wort below 180 risk goes substantially up. That's one reason we boil or we could just go right from mash to fermenter (besides the isomerization of hops).

The risk for infection goes up, you have hot-side aeration which can lead to off-flavors, and precursors for acetaldehyde go way up. There is a reason commercial brewers don't do this. You shouldn't either. Just aerate cooled wort.

jcaudill said:

I mean this in the nicest way possible: I don't care how sterile you think this is. It's not. Once you get the wort below 180 risk goes substantially up. That's one reason we boil or we could just go right from mash to fermenter (besides the isomerization of hops).

The risk for infection goes up, you have hot-side aeration which can lead to off-flavors, and precursors for acetaldehyde go way up. There is a reason commercial brewers don't do this. You shouldn't either. Just aerate cooled wort.

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+1 on the hot side aeration being an issue (an issue over 80° I believe). Making sure I didn't aerate too hot made a pretty decent difference in the final taste of all my beers.

On a side note though, I think there's quite a few more factors to the boil than sterilizing and hop use. You've got color change, dms boil off, and protein/tannin clumping (hot break) for a few big processes.

Either way, off topic. If you did figure out an inline aeration process, you'd need to sterilize it somehow without aerating hot wart.

True - there are other things going on in the boil. I guess I was using that to emphasize the point a bit

jcaudill said:

I mean this in the nicest way possible: I don't care how sterile you think this is. It's not. Once you get the wort below 180 risk goes substantially up. That's one reason we boil or we could just go right from mash to fermenter (besides the isomerization of hops).

The risk for infection goes up, you have hot-side aeration which can lead to off-flavors, and precursors for acetaldehyde go way up. There is a reason commercial brewers don't do this. You shouldn't either. Just aerate cooled wort.

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So somehow after you've recirculated boiling water through the pump and lines and sanitized them, enough bacteria get into the beer to cause a problem? It's very nearly a closed system.

All it takes is a single cell of bacteria to get in, multiply and then cause an off-flavor. Then put aside the sanitation issue, like I said before you have hot-side aeration that can cause off-flavors and you've setup precursors for acetaldehyde which will give your beer a sour or green apple type taste. It's not worth it after all that hard work.

Wait, are you suggesting that he's going to pump air or O2 into boiling wort? As I understand it he would aerate AFTER cooling the wort down to a reasonable level. Just using the recirculation system as a vector for aeration.

Lots of people recirc their hot wort through a chiller. Adding air or O2 once the wort is cooled via the chiller device is no different than other methods of aeration as far as sanitation. At least no worse than shaking a carboy, or dropping into an open bucket after chilling.

I used to aerate in line. I don't like it. Unless you have a huge O2 tank, it's really hard to tell how much you've actually aerated. I just did it not in line for the first time today. I won't be going back.

He's talking about aerating and cooling simultaneously - so yes as far as hot-side aeration that is the concern.

Sanitation speaking - adding cooled wort to hot wort is when you have a risk of bacterial issues. It is much more risky than a one-time transfer of cooled wort because you keep reintroducing cooled, bacteria susceptible wort to hot wort.

Pash91 said:

I used to aerate in line. I don't like it. Unless you have a huge O2 tank, it's really hard to tell how much you've actually aerated. I just did it not in line for the first time today. I won't be going back.

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It's very hard to gauge using O2. Commercial breweries use filtered air from an air compressor because it's impossible to over-aerate with plain air. This is how I do it as well - I have a Dewalt compressor, with a coalescing filter first to trap any liquids, and a super sterile air filter after to purify.

jcaudill said:

It's very hard to gauge using O2. Commercial breweries use filtered air from an air compressor because it's impossible to over-aerate with plain air. This is how I do it as well - I have a Dewalt compressor, with a coalescing filter first to trap any liquids, and a super sterile air filter after to purify.

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Oooo, I like that idea, not to mention it's probably a lot cheaper in the long run

And you have a compressor to use for other projects! Just don't use the same hose and definitely not regular compressor hose.

Unfortunately, I overlooked the simultaneous cool and aerate in my previous response. I meant to say to recirculate just to cool the wort. Then after cooling the wort it can be aerated. As far as aerating hot wort... I agree it's a very bad idea.

As I understand it he would aerate AFTER cooling the wort down to a reasonable level. Just using the recirculation system as a vector for aeration.

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Exactly.

After some more thought, I'm thinking I might just re-circ until the chiller outlet is where I want it, then hit it w/ the airstone for the final pass to the fermenter. Thoughts?

I have something like this in mind, but I'm not sure how best to bypass the airstone until it's completely chilled. Any ideas?