HSA during MASH in RIMS??

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Kalvaroo

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I have a RIMS system and I just recently noticed on my last batch I'm getting a lot of aeration while my mash is resting and recirculating... Is this any cause of concern?

I feel my lautering is uneven and is decreasing my efficiency so I'm considering introducing a sparge arm in my mash, which would definitely cause more aeration during my rests...

I know that during the boil a lot of oxygen is removed and I also know the benefits of O2 during the boil. As far as I know HSA is only an issue (depending on who you ask) with post-boiled wort...

Just a question...

-kal
 
Not to be contrary, since I don't brew on a RIMS system, but it seems to me like this might be one of the very few instances where a homebrewer might be concerned about HSA. This is more of a question than a piece of advice, but my understanding was that HSA occurs when oxygen is vigorously driven in to hot wort causing oxygen to REACT (not just dissolve) with fatty acids in the wort, generating oxidized fatty acids which present in packaged beer as oxidation flaws. Oxidized fatty acids will not, as far as I know, boil off.

Normal mashing procedures, mixing, lautering, and splashing on the homebrew scale just aren't enough to cause this kind of aeration, so most people don't have to worry, but if you're using a pump to continuously recirculate while mashing, and getting serious aeration, I think it may actually be something to worry about.

More advanced RIMS brewers should chime in, though, and set me straight on whatever parts of that I've gotten wrong.

You should definitely take this info with more than a couple grains of salt.
 
Hmm...I think George Fix (who pushed forward a lot of the HSA stuff) always argued that it was oxidation of melanoidins that caused problems. Where did you see fatty acids mentioned?

In any case, most commercial brewers are aggressively churning their mash tuns. Would this be any worse than that?
 
Hmm...I think George Fix (who pushed forward a lot of the HSA stuff) always argued that it was oxidation of melanoidins that caused problems. Where did you see fatty acids mentioned?

In any case, most commercial brewers are aggressively churning their mash tuns. Would this be any worse than that?

I will have to look up the source on the fatty acids bit. As for churning mash tuns, that's usually done with big paddles, which would be primarily submerged in the mash, and I would be surprised if it was that aggressive. You wouldn't be able to get that much speed pushing through thousands of pounds of mash- I would bet it's relatively slow, mostly submerged, and doesn't introduce a ton of air to the mash, but I could very well be wrong.
 
I not only mash with RIMS, but I use a cordless drill and cement mixer attachment to dough in/stir between sparges. Brewed this way for over a year successfully.
 
I have a RIMS system and I just recently noticed on my last batch I'm getting a lot of aeration while my mash is resting and recirculating... Is this any cause of concern?

I feel my lautering is uneven and is decreasing my efficiency so I'm considering introducing a sparge arm in my mash, which would definitely cause more aeration during my rests...

I know that during the boil a lot of oxygen is removed and I also know the benefits of O2 during the boil. As far as I know HSA is only an issue (depending on who you ask) with post-boiled wort...

Just a question...

-kal

What's causing the aeration? Is there air in your pump lines or is it splashing back into the MLT?
 
I will have to look up the source on the fatty acids bit. As for churning mash tuns, that's usually done with big paddles, which would be primarily submerged in the mash, and I would be surprised if it was that aggressive. You wouldn't be able to get that much speed pushing through thousands of pounds of mash- I would bet it's relatively slow, mostly submerged, and doesn't introduce a ton of air to the mash, but I could very well be wrong.

In liquid systems like this, all you really need is continuous surface turnover to introduce saturation levels of oxygen. At 150ºF or so, simply stirring gently for a few moments will saturate the liquid. I'm not sure why splashing would make things any worse.

Besides, if HSA is such an issue during the mash, why wouldn't it be an issue during the boil, where the higher temperatures would lead to ten times the average chemical reaction rate above mash temps?
 
Besides, if HSA is such an issue during the mash, why wouldn't it be an issue during the boil, where the higher temperatures would lead to ten times the average chemical reaction rate above mash temps?

Because oxygen is pretty soluble in wort at 160F, but not at all at 212. Plus, the surface oxygen contact of boiling wort is pretty minimal due to the rate of water vapor moving away from the surface.

Anyway, I'm no expert, it just seemed like this could be one of the very rare instances one might want to make adjustments.
 
Because oxygen is pretty soluble in wort at 160F, but not at all at 212. Plus, the surface oxygen contact of boiling wort is pretty minimal due to the rate of water vapor moving away from the surface.

Certainly, but if solubility is a limiting factor here, why would a bit of splashing from a sparge arm be the thing that makes the difference? Unless you're boiling your water before you mash, it comes into the equation already saturated above the 5ppm or so that 150ºF water will hold. Even if your water comes with low dissolved oxygen for some reason, the surface turnover will saturate it long before the mash is finished.
 
Certainly, but if solubility is a limiting factor here, why would a bit of splashing from a sparge arm be the thing that makes the difference?

Because I wasn't under the impression that the sparge arm splashing was the issue. OP said he was getting lots of aeration while recirculating his mash. If he's beating significant volumes of air into his hot wort with a pump, that seems to me to be about the only way a homebrewer could damage their beer with oxygen on the hot side.

Unless you're boiling your water before you mash, it comes into the equation already saturated above the 5ppm or so that 150ºF water will hold.

This is an excellent point, and one I hadn't considered, although it throws the entire concept of HSA (even on the professional scale) into question, if I'm thinking straight. I was under the impression that the pros still take caution to avoid HSA, and they have access to way more current brewing science literature than I do.

What's causing the aeration? Is there air in your pump lines or is it splashing back into the MLT?

This would be a good question to get an answer to.
 
Because I wasn't under the impression that the sparge arm splashing was the issue. OP said he was getting lots of aeration while recirculating his mash. If he's beating air into his wort with a pump, that seems to me to be about the only way a homebrewer could damage their beer with oxygen on the hot side.

Does it make a difference though for something like HSA? Obviously he doesn't want to be spewing foam everywhere, but saturation is saturation no matter where it comes from, no?
 
OP Here...

I have a brutus 10 clone and I'm using a Blichmann Auto-Sparge and March Pumps... I control the flow with a valve, so I"m not necessarily using the auto-sparge the way it was intended...

Anyway, the valve on the auto-sparge sucks in air when I adjust my flow where i need it... It's not a big deal, just sometimes makes a significant amount of foam in my mash tun, depending on the beer i'm brewing... I needed a new project and felt like introducing a sparge-arm into my system, and that's when i came up with my original question.

Since then...

I tried to build a sparge-arm which ended up being a big pain in the ass... So i just took the auto-sparge out of my system... no more bubbles...

Thanks for all the responses... ended up being an interesting topic.
 
MalFet said:
Hmm...I think George Fix (who pushed forward a lot of the HSA stuff) always argued that it was oxidation of melanoidins that caused problems. Where did you see fatty acids mentioned?

In any case, most commercial brewers are aggressively churning their mash tuns. Would this be any worse than that?

First off, George Fix is the man! Secondly, in his second edition of "principles of brewing chemistry" he talks about both fatty acids and melanoidans as potential substances to be oxidized at temps around 158F (70C). SO you are both right! how cool!

He shows that their products can produce off-flavors. An interesting finding, and one that I am now interested in. Especially since my new pump turned my mash foamy... I didn't take the proper amount of time in researching exactly how to use the thing before trying it. Oh well. The beer is tasting a little tart and I think it's either an infection, a fermentation problem or an HSA problem. Hard to know for sure...
 
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