Author Topic: Potassium metabisulfate  (Read 894 times)

Offline curtdogg

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Potassium metabisulfate
« on: March 25, 2018, 07:44:39 PM »
I'm thinking of adding a dose of K-meta to my keg to see if it will help preserve hop flavors and aroma.
I'm going to treat it like I would dextrose for bottling. Add it to the keg and transfer beer to mix.


Anyone have experience with this?

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Offline HighVoltageMan!

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Re: Potassium metabisulfate
« Reply #1 on: March 26, 2018, 02:50:46 PM »
I've been toying with the idea as well. I do closed transfer and avoid oxygen as much as humanly possible, but I looked into adding a 550mg tablet to the beer during transfer into the keg as an antioxidant. I wanted to avoid going above the 10ppm threshold, that's the maximum a commercial brewery can go without putting it onto the label (potassium metabisulfite contains @ 67% sulfite). I was looking at adding it to any beers I was looking to keep a little longer for comps, but I'm wondering if it will add a sulfur note to the beer.

As I looked into it, I found that BSG sells it as an antioxidant for beer. I also found out it's a fairly common antioxidant in beer outside the US.

Offline Robert

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Re: Potassium metabisulfate
« Reply #2 on: March 26, 2018, 03:00:13 PM »
When I used to use a coarse plate filter (trying not to lately) I would sanitize, then purge the keg and flush the filter with water dosed with K-meta.  I honestly don't know if it had a significant effect preserving aroma (filtration strips it anyway) but it made me feel I was doing my best to avoid oxidation. 
Rob
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Offline Aksarben

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Re: Potassium metabisulfate
« Reply #3 on: March 28, 2018, 01:29:49 AM »
10 ppm would be easy to figure.  We add SO2 all the time to our ciders and wines, at the winery.  I run the lab and do free and total SO2 pretty much all the time (I AM the lab guy) ;)  for each5  gallon, if you use 0.33g KMBS  (potassium metabisulfite) .  sssshhhh  here is the link for easy calculations:  http://digimodern.com/labcalc/  We made it up from our SCO Unix program we used all the time.  Now it's an online calculator.  Try to keep it to yourselves.

I would think 20 ppm would not be discernable.  The higher the pH the more KMBS you need to add and 20 is nothing at the pH of most beers.  The calculator in the link also shows Molecular ppm  (Free) for bottling, usually done at 0.9ppm Molecular.  Just change the pH and get the amount needed.  Remember, this is for wines and ciders, with pH ranges in the 2.98  to 3.70 ranges, even though it will figure higher and lower. 
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Offline ynotbrusum

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Re: Potassium metabisulfate
« Reply #4 on: March 28, 2018, 01:41:58 AM »
I know of one commercial brewer that does this to store their filter base for use to run from fermenter to bright tank.  They claim it keeps their filter free of oxygen when they run through it.  I can’t say it helps, because this is a decoction brewer that perhaps oxidizes its wort before the filter.   That is another topic.....
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Offline Robert

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Re: Potassium metabisulfate
« Reply #5 on: March 28, 2018, 02:18:54 AM »
Ynotbrusum: that sounds like my old idea.

Aksarben:  Haven't seen you around the forum lately!  We need experts like you. Thanks for the secret calculator, and maybe you can answer my next question:  Could I add K-meta along with finings such as isinglass?  Is there a reason they would need to be added with a separation in time, or could they be combined in one solution?
Rob
Akron, Ohio

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Offline curtdogg

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Re: Potassium metabisulfate
« Reply #6 on: March 28, 2018, 02:23:25 AM »
I know Brewtan B is a similar product but I'm asking because I have K-meta on hand.
Thanks for all the replies.

I'll try next time, I already kegged Sunday.

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Offline Big Monk

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Re: Potassium metabisulfate
« Reply #7 on: March 28, 2018, 02:35:59 AM »
Keep in mind that if you are adding Metabisulfite (Na or K), you need to account for the added K or Na and SO4 you get from scavenging.
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Offline Big Monk

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Re: Potassium metabisulfate
« Reply #8 on: March 28, 2018, 02:38:10 AM »
I know Brewtan B is a similar product but I'm asking because I have K-meta on hand.
Thanks for all the replies.

I'll try next time, I already kegged Sunday.

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Just FYI: they aren’t similar products. BTB is gallotannin based and binds to specific substances and Sulfites are essentially oxygen scavengers.
“We are what we repeatedly do. Excellence, therefore, is not an act, but a habit.” Aristotle

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Offline ynotbrusum

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Re: Potassium metabisulfate
« Reply #9 on: March 28, 2018, 02:39:26 AM »
Brewtan B is a shelf stability agent, as far as I know.  It is not an active antioxidant/Oxygen scavenger.  Rather it will prevent oxidation over time by preventing oxygen uptake that otherwise might occur.  I am willing to be corrected, but I heard the representative of the company describe it this way.
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Offline curtdogg

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Re: Potassium metabisulfate
« Reply #10 on: March 28, 2018, 02:41:16 AM »
I know Brewtan B is a similar product but I'm asking because I have K-meta on hand.
Thanks for all the replies.

I'll try next time, I already kegged Sunday.

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Just FYI: they aren’t similar products. BTB is gallotannin based and binds to specific substances and Sulfites are essentially oxygen scavengers.
Thank you sir, maybe I was tryimg to say they could be used for a similar purpose?

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Offline Big Monk

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Re: Potassium metabisulfate
« Reply #11 on: March 28, 2018, 02:42:03 AM »
Brewtan B is a shelf stability agent, as far as I know.  It is not an active antioxidant/Oxygen scavenger.  Rather it will prevent oxidation over time by preventing oxygen uptake that otherwise might occur.  I am willing to be corrected, but I heard the representative of the company describe it this way.

Brewtan prevents oxidation indirectly by precipitating our compounds that have the potential for downstream staling reactions. As you said, it doesn’t, in any way, scavenge Oxygen or prevent oxygen uptake into wort/beer.
“We are what we repeatedly do. Excellence, therefore, is not an act, but a habit.” Aristotle

"Messieurs, c’est les microbes qui auront le dernier mot." Louis Pasteur

Check us out at www.lowoxygenbrewing.com

Offline Big Monk

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Re: Potassium metabisulfate
« Reply #12 on: March 28, 2018, 02:45:02 AM »
I know Brewtan B is a similar product but I'm asking because I have K-meta on hand.
Thanks for all the replies.

I'll try next time, I already kegged Sunday.

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Just FYI: they aren’t similar products. BTB is gallotannin based and binds to specific substances and Sulfites are essentially oxygen scavengers.
Thank you sir, maybe I was tryimg to say they could be used for a similar purpose?

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No I don’t think so, at least not in the way originally described in the OP.
“We are what we repeatedly do. Excellence, therefore, is not an act, but a habit.” Aristotle

"Messieurs, c’est les microbes qui auront le dernier mot." Louis Pasteur

Check us out at www.lowoxygenbrewing.com

Offline curtdogg

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Re: Potassium metabisulfate
« Reply #13 on: March 28, 2018, 02:47:43 AM »
I know Brewtan B is a similar product but I'm asking because I have K-meta on hand.
Thanks for all the replies.

I'll try next time, I already kegged Sunday.

Sent from my SM-G930P using Tapatalk

Just FYI: they aren’t similar products. BTB is gallotannin based and binds to specific substances and Sulfites are essentially oxygen scavengers.
Thank you sir, maybe I was tryimg to say they could be used for a similar purpose?

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No I don’t think so, at least not in the way originally described in the OP.
Understood.
Well I guess I should try it out and maybe put a bug in Marshals ear. Unless there has been an exBEERiment done already.

Thanks Big Monk.

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Offline Robert

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Re: Potassium metabisulfate
« Reply #14 on: March 28, 2018, 02:50:38 AM »
Brewtan B is a shelf stability agent, as far as I know.  It is not an active antioxidant/Oxygen scavenger.  Rather it will prevent oxidation over time by preventing oxygen uptake that otherwise might occur.  I am willing to be corrected, but I heard the representative of the company describe it this way.
Right, all explanations I have seen can be summed up as, it removes (to some degree)  what might be oxidized, sidelining (to some degree)  the issue of oxygen uptake.  Note though that Joe Formanik (said rep) talks on an MBAA podcast about adding it to the BBT to aid in clarification,  so it has applications right through the process that may overlap with what the OP is thinking about. Everything we're talking about is "shelf life stability."
Rob
Akron, Ohio

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