Keeping o2 out of the brewhouse

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Techbrau
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Re: Keeping o2 out of the brewhouse

Postby Techbrau » Mon Dec 07, 2015 11:45 am

1 ml of oxygen weighs 1.43 mg, so dissolved in 1 liter of wort this gives 1.43 ppm. Fix states that this is enough oxygen to induce staling reactions within seconds at 158 F. Kunze also has some plots in his book showing the rate of mashing oxidation reactions. IIRC it literally takes less than a couple of minutes for the irreversible damage to be done.

I find it interesting that it didn't occur to Fix at all that the initial oxygen concentration of brewing water at mashing temperatures is going to be approximately 6ppm.

I also found it very interesting that Narziss' research from the 1970s was so influential that it inspired breweries all across Europe to invest in low O2 equipment. And we now know that their brewing water is degassed to less than 0.1 ppm oxygen as well...
If you always do what you've always done, then you'll always get what you've always gotten.
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Roachbrau
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Re: Keeping o2 out of the brewhouse

Postby Roachbrau » Mon Dec 07, 2015 12:06 pm

Weizenberg, I don't think your water composition is going to change at all. CaCO3 will only precipitate to a threshold concentration of Ca, which I believe is way above your existing mineral levels. I have noticed no change at all in pH readings/amount of acid necessary to hit targets, even though my CO3 is 63ppm, but because all my other minerals are 25ppm or less, there's nothing for the CO3 to attach itself to in order to precipitate.

You could verify this by taking pH samples of your water before and after boiling.
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Weizenberg
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Re: Keeping o2 out of the brewhouse

Postby Weizenberg » Mon Dec 07, 2015 1:23 pm

Indeed. I confused it with boiling off the extra hardness which we had to do when in an region of hard water. That was quite a few years back. It doesn't hurt to heat the "hauptguss" a little higher and then use it. What was on my mind then was the 40 minute boil off regime -- which I dread.

On the other side I quite like the idea of a combination heating the water then using co2 for the finish. It seems faster to me.

There will be a reasonable middle-ground somewhere. Time is an issue for me.

My focus is currently on water composition, so I am anxious not disturbing it by any means.

When I decoct I always transfer very carefully, avoiding any o2 intake (that's how I learned it).

I am not sure one has to be 100% o2 free. Time and many happy drinks inbetween, will tell ;)
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Techbrau
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Re: Keeping o2 out of the brewhouse

Postby Techbrau » Mon Dec 07, 2015 1:27 pm

I think traditional Bavarian lager brewing techniques did a lot to fight oxidation.

Preboiling to remove alkalinity also removes oxygen.

Doughing in at the acid rest temperature slows oxidation reactions, and washes away the starch and amylase enzymes. Most of the LOX enzymes are found in the husk where it meets the arcospire. If the crush preserves the husk, LOX will not leech quickly into the wort. Pulling the first decoction and boiling it will denature LOX before it has a chance to inflict damage on the main mash.

Additionally, decoction boils create melanoidins which are powerful antioxidants and can fight oxygen as it diffuses into the main mash.

Just some food for thought.
If you always do what you've always done, then you'll always get what you've always gotten.

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