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Oxidation - a new friend

DJAllen said:
brewfun said:
HSA has a lot of variables and is a complex reaction. It only takes a few really basic and often intuitive steps to avoid it, altogether.


And I know I shall be kicking myself when I find out just what of the few really basic steps I should have been taking to avoid my oxidation nightmare....


I've read there is a test you can do to detect Hot side aeration. Don't know a lot about it, but perhaps you can narrow down the culprit that way. It uses a chemical called dichloro indophenol which changes color when added to the wort and the amount of time it takes indicated the level of hot side aeration.
 
grathan said:
It is commonly said that dry yeast doesn't require oxygenation.
It's in textbooks used by most of the brewing schools. But, I must let you know that it's in a chapter devoted to yeast health that says that's about the worst way to manage yeast.

I don't know the reasoning here, but let's assume the science is correct. By the same theory if you pitch liquid yeast that is also of a large quantity and heavily oxygenated, that that has to be a similar concept.

IF that were ACTUALLY science.... But, it's a very recent development where a major, respected and reliable packaged yeast company started drying their yeast with an oxidizer. Empirical evidence showed that this yeast started faster when pitched directly into wort than if it were rehydrated in water.

From my experiences my beers have improved since I have stopped blasting them with pure O2. I use a 2L stirred starter on 1.050 batch ( I couldn't tell if this is overpitched by experts' standards, but I am guessing that it may be )

My thoughts are that if your yeast pitch is oxygenated and is of large enough quantity, there will be very little growth and therefore very little oxygen consumption. And possibly this leftover o2 will end up hurting your batch. I know this is wild speculation and I unfortunately I don't have a dissolved o2 meter to prove it wrong...

This is sound judgement. Yes, unused O2 can become a staling issue later. Yes, going in with 100% or more of the viable yeast needed for the gravity and volume eliminates growth.

But, let's discuss the implications of this. If your yeast needs no growth, then it needs no nutrient, amino acids, proteins or to reduce it's own byproducts, either. But, it will use those things quickly. and in a constant need for nutrients will turn to autolysis to find it.

It will multiply by at least one generation, which doubles your pitching rate. The yeast now has more volume, which takes up beer. Plus, higher yeast populations often have a harder time flocculating.

The yeast calculators tend to get you to where one to three doublings of yeast populations occur. This is the most complete use of nutrients possible. It builds healthier cell walls and increases the yeast's ability to flocculate as key wort components are used up.

Grathan, if what you're doing has improved the quality of your beer, keep doing it! You're procedure is fine, but the logic behind it is the smashing together of two different procedures and goals. 
 
You want some ester production. For me its just the simpliest way to get some flavor. Some day I would be tracking fermenation vessel pressure, wort thickness, ferm temp, and adjusting my o2 injection accordingly based on yeast strain. Just not there yet.
 
I would second oxygen and storage temps.  You're beer will fall apart at room temperature within a couple of months.  Especially a lighter SRM with hoppy character.
 
I guess I would have to ask... are you 100% sure it's oxidation?

Maybe some other off flavor?

Just asking.
 
The only reason I ask that is because I have sat, on many occasions, between 2 very qualified BJCP certified judges (whatever that is worth) and heard them disagree about what the off flavor is. You must be sure it is oxidation. If not, you may be chasing the wrong rat.
 
Hi Freak,

I suspect you may be right. After a short vacation, I had chance to brew another all grain IPA batch but taking care to avoid any hot-side aeration as suggested by others previously on this thread. I started with an OG of 1.065 that dropped to 1.012 at day 3 (70F) and it tasted as you'd expect. I left the batch undisturbed in the fermentor until bottling at day 5 (FG 1.011) and guess what - that obvious green beer taste and the harsh hoppiness from day 3 had faded significantly and it was well on its way to bland with a slight wet cardboard taste. Thinking over my process, I'm wondering if my failure to attempt to remove hot and cold break trub might be the issue?

D
 
I like long, cool fermentations - at least two weeks at or below the manufacturer's recommended minimum. So, I can usually find a way to blame any flaw on fermentation time or temperature. Fermenting at 70F for three days and bottling at five days seems too warm and too fast. Try another batch with fermentation between 60 and 65F. Let it ferment for two weeks and check the gravity; if the gravity is stable over three days, raise the temp to 70 for another week, then bottle.

Now comes the caution: I'm highly prejudiced on the issues of fermentation time and temperature. This advice does not come with a money-back guarantee; use it at your own risk.
 
durrettd said:
Fermenting at 70F for three days and bottling at five days seems too warm and too fast.

Couldn't agree more but a quick ferment and no secondary was deliberate choice on my part to limit the time in the plastic fermenter. Just one of the variables I've eliminated in nailing the cause of my grief. Besides, my problem seems to be going in the wrong direction - instead of the increased character of a high temp ferment, I'm getting an increasing blandness.

I'm gonna focus on removing hot & cold break nasties next as these have all gone into my fermenter in the past....
 
I've found that some of my most bland beers have been the more complex grain bills.  My simpler recipes are rarely bland.
 
Scott Ickes said:
I've found that some of my most bland beers have been the more complex grain bills.  My simpler recipes are rarely bland.

Can happily rule that one out - it's just 6.5kg of marris otter and hops. Couldn't be more simple and no better bill to test for oxidation!
 
DJAllen said:
Scott Ickes said:
I've found that some of my most bland beers have been the more complex grain bills.  My simpler recipes are rarely bland.

Can happily rule that one out - it's just 6.5kg of marris otter and hops. Couldn't be more simple and no better bill to test for oxidation!

Agreed!
 
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