Author Topic: Mash Caps  (Read 1401 times)

Offline narcout

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Mash Caps
« on: December 02, 2016, 09:13:54 PM »
Have any of you who mash in coolers fabricated a mash cap for low oxygen brewing?

I was thinking about getting something like the below and trimming it down to size (need to measure my tun to figure out what size I need).

https://www.amazon.com/Kitchen-Silicone-Nonstick-Fondant-Counter/dp/B015PTPOHY/ref=sr_1_5?ie=UTF8&qid=1480713139&sr=8-5&keywords=large+silicone+baking+mat
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Offline Stevie

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Mash Caps
« Reply #1 on: December 02, 2016, 09:19:49 PM »
I don't know how well it will float. While it would be less dense than water, I think a slight break in the surface would cause it to go down. This is because of the flexibility. A more rigid solution might work better.

ETA - it's cheap enough to give it a shot.

Offline HoosierBrew

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Re: Mash Caps
« Reply #2 on: December 02, 2016, 09:25:05 PM »
I used several layers of foil, sort of rolled and crimped on the ends. The foil was slightly bigger than the inside of the cooler, so that I could mold it to the edges and corners. Not sure if it's a long term solution but it turned out a really tasty beer.
Jon H.

Offline Stevie

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Re: Mash Caps
« Reply #3 on: December 02, 2016, 09:30:04 PM »
I used several layers of foil, sort of rolled and crimped on the ends. The foil was slightly bigger than the inside of the cooler, so that I could mold it to the edges and corners. Not sure if it's a long term solution but it turned out a really tasty beer.
I imagine your rolled edges create rigidity. Aluminum isn't an issue?

Offline beersk

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Re: Mash Caps
« Reply #4 on: December 02, 2016, 09:34:32 PM »
I used several layers of foil, sort of rolled and crimped on the ends. The foil was slightly bigger than the inside of the cooler, so that I could mold it to the edges and corners. Not sure if it's a long term solution but it turned out a really tasty beer.
I imagine your rolled edges create rigidity. Aluminum isn't an issue?
I asked Bryan this and he didn't seem to think aluminum was a problem...
die Schönheit der bier...

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Offline HoosierBrew

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Re: Mash Caps
« Reply #5 on: December 02, 2016, 09:39:10 PM »
I used several layers of foil, sort of rolled and crimped on the ends. The foil was slightly bigger than the inside of the cooler, so that I could mold it to the edges and corners. Not sure if it's a long term solution but it turned out a really tasty beer.
I imagine your rolled edges create rigidity. Aluminum isn't an issue?


The egdes were loosely enough rolled together to still let me mold it for the contours of the cooler. You mean a safety issue? I've read of guys using foil for a mash cap. It was cheap and around. Iknow there are different grades of aluminum but lots of brewers still use cheap aluminum kettles.
Jon H.

Offline Stevie

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Mash Caps
« Reply #6 on: December 02, 2016, 10:46:03 PM »
I wasn't thinking safety as much as causing some anti low o2 voodoo

Offline mabrungard

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Re: Mash Caps
« Reply #7 on: December 03, 2016, 01:07:09 AM »
I just made a mash cap out of 1/2" thick closed cell foam yoga mat or camping ground pad material. It works well. Its easy to cut to shape. I did add some 1/4" wood strips to the top of the cap to serve as stiffeners. I used Goop to glue the strips onto the foam. Goop is full of nasty smelling volatiles, so it took several days of airing out for the smell to go away. But the good thing about Goop is it has a tenacious grip. Silicone glue would be less toxic initially, but it doesn't stick well enough.

I do have a piece of aluminum flashing bolted with SST bolts on the underside of the cap to deflect the return flow along the underside of the cap. Aluminum is not a problem for use in wort since it is essentially insoluble when the pH is between 4.5 and 8.5. It will corrode when the pH is outside that range. We are safe to use aluminum in the mash tun and kettle.

I tried making a mash cap out of corroplast material, but that warps badly when heated and I could get the hollow cells sealed well enough.
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Offline HoosierBrew

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Re: Mash Caps
« Reply #8 on: December 03, 2016, 01:17:01 AM »
I just made a mash cap out of 1/2" thick closed cell foam yoga mat or camping ground pad material. It works well. Its easy to cut to shape. I did add some 1/4" wood strips to the top of the cap to serve as stiffeners. I used Goop to glue the strips onto the foam. Goop is full of nasty smelling volatiles, so it took several days of airing out for the smell to go away. But the good thing about Goop is it has a tenacious grip. Silicone glue would be less toxic initially, but it doesn't stick well enough.

I do have a piece of aluminum flashing bolted with SST bolts on the underside of the cap to deflect the return flow along the underside of the cap. Aluminum is not a problem for use in wort since it is essentially insoluble when the pH is between 4.5 and 8.5. It will corrode when the pH is outside that range. We are safe to use aluminum in the mash tun and kettle.

I tried making a mash cap out of corroplast material, but that warps badly when heated and I could get the hollow cells sealed well enough.



I like that idea for a more permanent solution. Thanks, Martin!
Jon H.

Offline The Beerery

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Re: Mash Caps
« Reply #9 on: December 03, 2016, 03:04:55 AM »
Yea, Aluminum foil can work and its cheap, and easy enough to mold to whatever. Uee it to cap your preboil, and all the vessels on transfers, since it will adhere pretty tight and float as the volumes increase/decrease.
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Offline BairsBrewing

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Re: Mash Caps
« Reply #10 on: December 03, 2016, 04:16:57 AM »
Yoga mats? Like Subway?  There's gotta be a better way,  IMO

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Offline The Beerery

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Re: Mash Caps
« Reply #11 on: December 03, 2016, 04:24:09 AM »
Yoga mats? Like Subway?  There's gotta be a better way,  IMO

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There is. We speak about it here: http://www.lowoxygenbrewing.com/uncategorized/limiting-oxygen-exposure-on-the-hot-side-via-caps/

Though it's not a 1 size fits all solution, nor "cheap".
Herr, wirf Hirn vom Himmel!
(Oder Steine, Hauptsache er trifft.)
Check us out at www.lowoxygenbrewing.com (Now with forums)
"Consistently successful brewers are invariably the ones who operate low oxygen systems." -George Fix Circa 1999
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Offline BairsBrewing

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Re: Mash Caps
« Reply #12 on: December 03, 2016, 04:34:21 AM »
What about when you use a RIMS system? Also, does it make that much of a difference at the micro level of 5 gallon batches?

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Offline The Beerery

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Re: Mash Caps
« Reply #13 on: December 03, 2016, 01:36:48 PM »
What about when you use a RIMS system? Also, does it make that much of a difference at the micro level of 5 gallon batches?

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Doesn't matter what type of mashing system is used. The smaller the batch the more important it is.
Herr, wirf Hirn vom Himmel!
(Oder Steine, Hauptsache er trifft.)
Check us out at www.lowoxygenbrewing.com (Now with forums)
"Consistently successful brewers are invariably the ones who operate low oxygen systems." -George Fix Circa 1999
Taplist and Fermentation Cellar
"Progress is impossible without change, and those who cannot change their minds cannot change"

Offline homoeccentricus

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Re: Mash Caps
« Reply #14 on: December 03, 2016, 03:02:01 PM »
I have this one: http://vlaamshobbybrouwforum.be/forum/index.php?topic=4753.msg86029#msg86029

Silicone mat not for baking, but for rolling out dough. You have to be sure that it floats :)
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