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-   -   HSA during MASH in RIMS?? (http://www.homebrewtalk.com/f36/hsa-during-mash-rims-372066/)

Kalvaroo 12-05-2012 05:30 AM

HSA during MASH in RIMS??
 
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

MalFet 12-06-2012 12:06 AM

Whatever oxygen you introduce during the mash will be driven off during the boil. It's really not a concern.

daksin 12-06-2012 10:47 PM

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.

MalFet 12-06-2012 11:27 PM

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?

daksin 12-06-2012 11:46 PM

Quote:

Originally Posted by MalFet (Post 4657322)
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.

jammin 12-06-2012 11:53 PM

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.

helibrewer 12-06-2012 11:55 PM

Quote:

Originally Posted by Kalvaroo (Post 4651012)
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?

MalFet 12-07-2012 12:32 AM

Quote:

Originally Posted by daksin (Post 4657376)
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 150F 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?

daksin 12-07-2012 06:04 PM

Quote:

Originally Posted by MalFet (Post 4657511)
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.

MalFet 12-07-2012 06:36 PM

Quote:

Originally Posted by daksin (Post 4659886)
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 150F 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.


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