Author Topic: Examining Oxygen Ingress: Should I Pre-boil?  (Read 7159 times)

Offline brewinhard

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #15 on: June 30, 2017, 05:35:41 pm »
I perform full volume no-sparge beers (6 gallon batches) and with a typical 8.5-9 gallons of water to heat up it usually takes about 50 minutes to get to a boil. After the quick 5 min boil, it only takes about 5 minutes or so to bring it down to strike temps.

During the wait for the boil I take care of measuring out my salts, antioxidants, condition my grains, and mill them. My total brewday is always under 5.5 hrs even with the pre-boiling included. Pretty much the same as before (sometimes less).

Offline yso191

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #16 on: July 01, 2017, 10:37:12 am »
What is SMB?
Steve
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Big Monk

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #17 on: July 01, 2017, 10:45:11 am »
What is SMB?

SMB = NaMeta = Sodium Metabisulfite

KMB = KMeta = Potassium Metabisulfite

Found either in powdered form or in tablet form (Campden). It's used in this context as an Oxygen scavenger.

Offline yso191

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #18 on: July 01, 2017, 11:30:52 am »
 Thank you
Steve
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Offline homoeccentricus

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #19 on: July 02, 2017, 03:23:58 am »
How about a combination of yeast and preboil methods? Say half the regular amount of yeast/sugar for 30 minutes and heating to 85C? This could reduce time and energy. Does anyone have any yeast/sugar/time vs DO ratios?
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Offline homoeccentricus

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #20 on: July 02, 2017, 04:00:06 am »
There's some calculations here: http://forum.germanbrewing.net/viewtopic.php?f=50&t=355&start=30#p3960

Using the regular amount of yeast/sugar, 7 ppm DO is reduced to 1.31 ppm in 24 minutes. Then heating from 30C to 72C will eliminate all oxygen, given the process is linear. If the yeast method creates some off-flavors, it should be measured what will be the gain if the amount of yeast/sugar is decreased. Also, what would be the additional DO-reduction by the yeast while it is still active during the heating. There's some additional information from Bilsch here: http://forum.germanbrewing.net/viewtopic.php?f=50&t=355&start=30#p3960:

"Increase water temp to 44c and transfer with underletting to the grain. Was 40/60 pils/wheat (+6.5% C125) grain bill. The idea here being to dough in at a temperature where yeast would still be active, let it do it's O thing.. then ramp up to beta and alpha.
DO at transfer was 0.29 mg/l"
« Last Edit: July 02, 2017, 04:08:55 am by homoeccentricus »
Frank P.

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Offline homoeccentricus

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #21 on: July 02, 2017, 04:04:53 am »
The other idea I had was: since I buy water in 5L jerrycans, I might add yeast/sugar to one or more of them the night before I brew, and add that deoxygenated water cold to the mash tun after having heated the water to 70-80C.  Because I also do not like having to use the wort chiller at this stage of the brewing process. Complicates things for me...
« Last Edit: July 02, 2017, 04:08:12 am by homoeccentricus »
Frank P.

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Offline natebrews

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #22 on: July 02, 2017, 05:20:56 am »
I would think that the transfer from the jerrycans to the tun would be an additional point of pickup that you could avoid.  Could you put the water in the tun the night before and leave that overnight?  I'm assuming you have a heated mashtun in this scenario.
Risk of failure should be no deterrent to trying.

Big Monk

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Examining Oxygen Ingress: Should I Pre-boil?
« Reply #23 on: July 02, 2017, 08:02:21 am »
I'm going to be doing some trials where I brew with only heating to strike temp, 185 °F (85 °C) and full preboil.

I'll be interested to see if the impacts of increased Sulfate levels from my larger doses affect the final beer. Early results coming in from people have shown that higher sulfite loads give some undesirable characteristics. So far I have only preboiled but I'm looking to give some data points here.

As Martin said above, you should make sure your "house is in order" (mash cap, limit by all other means, etc) before playing with dosing and I agree. That's part of the reason I put the disclaimer in the blog post. Yet if I can streamline my day at all and not affect final quality, I'll try that out as well.

« Last Edit: July 02, 2017, 08:05:30 am by Big Monk »

Offline yso191

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #24 on: July 02, 2017, 10:18:03 am »
 I have a very limited understanding of this low oxygen brewing. I'm also lazy. So I'm considering which aspects of it would give me the biggest bang for my effort.  I currently use Brewtan B.   I am also quite scrupulous with exposure to oxygen post fermentation. But given that this thread is on pre-boiling mash water, how much of that oxygen is left in the wort after the 60 minute boil?   And whatever is left, isn't that scavenged by the yeast  during fermentation? 

 I recognize that these questions may have been asked before but I just don't want to put forth effort and potential cost for something that is a not discernible in the final product.   So to re-state, I don't question the underlying principles involved in low dissolved oxygen brewing. I just want to know where the tipping point is for what makes a discernible difference in the beer.   Please don't hear this that I'm criticizing or flaming anyone  or any other perspective, I am just looking for where I choose to settle in this area of science.
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Big Monk

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #25 on: July 02, 2017, 11:42:25 am »
I have a very limited understanding of this low oxygen brewing. I'm also lazy. So I'm considering which aspects of it would give me the biggest bang for my effort.  I currently use Brewtan B.   I am also quite scrupulous with exposure to oxygen post fermentation. But given that this thread is on pre-boiling mash water, how much of that oxygen is left in the wort after the 60 minute boil?   And whatever is left, isn't that scavenged by the yeast  during fermentation? 

 I recognize that these questions may have been asked before but I just don't want to put forth effort and potential cost for something that is a not discernible in the final product.   So to re-state, I don't question the underlying principles involved in low dissolved oxygen brewing. I just want to know where the tipping point is for what makes a discernible difference in the beer.   Please don't hear this that I'm criticizing or flaming anyone  or any other perspective, I am just looking for where I choose to settle in this area of science.

One of the main points is that there exists a flavor component in malt that when exposed to Oxygen is volatilized very rapidly. One thing you'll notice if you limit Oxygen is the suppression of mash smells in the brewery.

A dissolved oxygen level on the order of 1 ppm throughout the entire hot side is enough to render the process moot.

So there are a few points to think about here:

1.) Pre-boiling totally eliminates Oxygen from the mash water. It gives the most margin.

2.) Whether you pre-boil or not, you need active scavengers (metabisulfite) to combat the Oxygen levels brought on by:

   a.) O2 solubility at mash temps (4-5 ppm)

   b.) Mash-in ingress (1-3 ppm)

   c.) Atmospheric diffusion (1-2 ppm/hr)

3.) Capping your mash can mitigate much of c.)

4.) Carefully doughing-in can limit b.)

5.) You CAN get by if you make all other improvements to your process (capping, limiting through mechanical means, tightening hose connections and fittings, etc.) but it comes at the expense, as some have mentioned, of increasing your Sulfate content.


Offline homoeccentricus

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #26 on: July 02, 2017, 12:05:56 pm »
I would think that the transfer from the jerrycans to the tun would be an additional point of pickup that you could avoid.  Could you put the water in the tun the night before and leave that overnight?  I'm assuming you have a heated mashtun in this scenario.
Actually yes, I bring my stuff up from the basement when I brew in the morning, or take it to the Homebrew club...
Frank P.

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Offline yso191

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #27 on: July 02, 2017, 12:28:24 pm »
 Thank you Big Monk.   Do you know how much of the oxygen that is introduced in the mash survives the boil? And then how much survives fermentation?
Steve
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Big Monk

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #28 on: July 02, 2017, 12:34:57 pm »
Thank you Big Monk.   Do you know how much of the oxygen that is introduced in the mash survives the boil? And then how much survives fermentation?

None and none. The point though is that if you have greater than 1 ppm on the hot side, you've negated the effort.

Offline Wilbur

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Re: Examining Oxygen Ingress: Should I Pre-boil?
« Reply #29 on: July 02, 2017, 02:27:25 pm »
Thanks BM for the quick summary, I've been looking through a lot of material and thinking about trying find things out. I think this was really helpful in evaluating the impact. How quickly does the volitizaton occur, and how does temperature impact this? I've always kind of wondered how chilling and introducing O2 for yeast use impacts these chemicals. I know I've heard from Jamil that yeast will scavenge oxygen almost immediately during fermentation, but I've never been sure.

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