Mash Caps... Let me see what you got!

[DonT]

Okay, so I want to implement a mash cap and was thinking about purchasing the NorCal Brewing set-up. @Bilsch and Bracc (RIP) had helped design it, but it needs more.
Has anybody used that piece, either the way it was sold or any mods to it? If not, what's your set-up? Pictures appreciated. I have a Spike 15G mash tun in an eHERMS set up and I fly sparge.
Thanks!

 

[JAReeves]

I used one for the first time with my last brew, and I got 20% less efficiency. What’s the benefit of a mash cap?

I may have done other things wrong; 1st time using an AIO as a mash tun with recirculating and temp control.

 

[ba-brewer]

I have not used that part, but cool to see Bracc getting credit.

I use a stainless steel cake pan which covers maybe 90% of the surface. My return in on the edge where I can see the flow, helps to identify a stuck mash.

I have two of these atomization nozzles on a tee on the return under the surface to slow the flow.
atomization nozzles

edit- that is not the exact nozzle I am using as it is no longer available on amazon but similar in a 1/2 thread.

 

[Red over White]

This is my floating mashcap. Made it from a cake pan and the spare parts bin. It doesn't produce turbulence on the surface at full bore recirc. Fugly, but effective.

 

[DonT]

This is my floating mashcap. Made it from a cake pan and the spare parts bin. It doesn't produce turbulence on the surface at full bore recirc. Fugly, but effective.

Nice. Does the outlet spray cause it to dig into the mash?

 

[bailey mountain brewer]

 

[Red over White]

Nice. Does the outlet spray cause it to dig into the mash?

No, I use a TD5 pump and it hits the bottom of the pan, then the ring on the bottom slows it down even more for a gentle recirculation.

 

[Bobo1898]

I used one for the first time with my last brew, and I got 20% less efficiency.

I've been thinking about implementing a mash cap for a bit and while efficiency will change as your system evolves, a 20% swing seems a bit extreme. Has anyone else had efficiency issues like this?

 

[day_trippr]

I wouldn't lose motivation over that report - there was way more at play than just a mash cap.

1st time using an AIO as a mash tun with recirculating and temp control.

Cheers!

 

[JAReeves]

I wouldn't lose motivation over that report - there was way more at play than just a mash cap.



Cheers!

I agree. I think mistakes were made, Senator.

 

[Bobby_M]

I do not agree that a perforated plate qualifies as a mash cap, at least in the most common usage of the word in the LODO community. I mean, if you want to spit hairs and suggest that reducing the mash's exposure to only 40% instead of 100%, sure. It's just a matter of whether that's enough to make any difference. My instinct is that it's about the same as just putting a lid on the pot. A true mash cap is a pretty good seal to the perimeter of the mash vessel and if there is recirculation, that should exit underneath the sealed cap.

I think the confusion about this was derived from the fact that many of the all in one brewing systems include some kind of perforated disc for the top of the mash to diffuse the incoming recirculated mash liquor. I never really understood the point. There are less expensive ways of diffusing the flow to keep it from boring down into the mash and there is usually an effective depth of liquid-only mash on the top, almost making diffusion unnecessary, at least at the lower flow rates you'd want to maintain.

 

[JohnDBrewer]

I agree with Bobby, I don't see this as an effective mash cap. Also seems like any splashing of the wort/sparge water is counter productive. Why not just use a piece of foil? I use a lid on my mash tun for temp stability, but maybe there's more to it.

 

[scrap iron]

I have an old 16-gal keg for a mash tun. I used a 1" thick piece of hard foam insulation covered with heavy duty aluminum foil. It is folded over at the top. I made it the inside diameter of the keg and cut it in halve to fit inside the keg easier. There is a hole in the center for the recirculation. The cap floats on top of the liquid level with an old SS 90 tube pinched shut at the end that I drilled holes in pushed into the tubing for the recirculation. The top of the keg is cut to fit a lid on to help keep the heat in, but the foam board material does a good job by itself. I use Brewtan B so I don't worry about the aluminum foil.
https://www.homedepot.com/p/Project...Foam-Board-Insulation-Sheathing-PP1/203553730

 

[DonT]

I do not agree that a perforated plate qualifies as a mash cap, at least in the most common usage of the word in the LODO community. I mean, if you want to spit hairs and suggest that reducing the mash's exposure to only 40% instead of 100%, sure. It's just a matter of whether that's enough to make any difference. My instinct is that it's about the same as just putting a lid on the pot. A true mash cap is a pretty good seal to the perimeter of the mash vessel and if there is recirculation, that should exit underneath the sealed cap.

I think the confusion about this was derived from the fact that many of the all in one brewing systems include some kind of perforated disc for the top of the mash to diffuse the incoming recirculated mash liquor. I never really understood the point. There are less expensive ways of diffusing the flow to keep it from boring down into the mash and there is usually an effective depth of liquid-only mash on the top, almost making diffusion unnecessary, at least at the lower flow rates you'd want to maintain.

Agreed. I like the way it would diffuse the wort flow, but yes, the screen sits below the wort and does nothing to seal it from air. That's what I was referring to when I said it's needs more... more sealing. And since it's the only commercial thing out there, I was wondering if anybody has purchased it and somehow created a lid for it. And it's a bit expensive. This is all why I wanted to see what folks had come up with on their own.

I was perusing Amazon for something that would work, like a SS pizza pan. Couldn't really find a SS one in the correct size, but plenty in aluminum. I'm hesitant about using AL in the wort, though, @scrap iron says brewtan b would protect against that. Seeing what @Red over White came up with has given me some ideas.

 

[Bobby_M]

I made mine from a stainless pot lid that was a bit smaller than the ID of my kettle and used food grade silicone RTV to glue a sweeper gasket to the edge. It will hold position however I push it into the kettle. I'm not at the shop right now but I'll take a picture tomorrow.

 

[Bassman2003]

Yes, a true "mash cap" is floating and used to prevent surface exposure to oxygen. There should be no correlation with mash efficiency.

Another important part of using a mash cap is turning your pump speed way down (if you are using a recirc pump).

I made a video about mash caps if anybody is wondering:

 

[DonT]

I made mine from a stainless pot lid that was a bit smaller than the ID of my kettle and used food grade silicone RTV to glue a sweeper gasket to the edge. It will hold position however I push it into the kettle. I'm not at the shop right now but I'll take a picture tomorrow.

Interested in that sweeper gasket... link?

 

[Bobby_M]

https://www.mcmaster.com/12335A63/

 

[mabrungard]

I use a closed cell foam that was originally a kids nap pad. It’s cut to fit my tun tightly. There’s a 90 degree hose fitting in the center of the pad that directs flow directly downward through the pad and I’ve bolted a thin sheet of aluminum over the fitting outlet to spread the flow horizontally over the mash bed.

This mash cap almost completely isolates the mash and wort from air contact. I find that it works really well.

 

[IslandLizard]

https://www.mcmaster.com/12335A63/

Sorry, McMaster wants a login to show the link.
Could you post an image or so?

 

[day_trippr]

I have a feeling I've seen that wiper gasket before. See the cross-sectioned segment at ~10:30...

This is what's on the M-C page @Bobby_M linked...

Cheers!

 

[DonT]

Ok Ladies and Gents, here's what I came up with...
I used my loc-line sparge circle and inverted it to the bottom of a SS lid.

With the nozzles pointed up, it'll deflect the flow and won't drill into the mash. Next is to add a seal which I think will just be something like 3/8 silicone hose with a slice to fit over the edge of the rim, glued on.

 

[Unicorn_Platypus]

View attachment 832727
I use a closed cell foam that was originally a kids nap pad. It’s cut to fit my tun tightly. There’s a 90 degree hose fitting in the center of the pad that directs flow directly downward through the pad and I’ve bolted a thin sheet of aluminum over the fitting outlet to spread the flow horizontally over the mash bed.

This mash cap almost completely isolates the mash and wort from air contact. I find that it works really well.

Martin is that material food grade though? Would be my only concern about it

 

[Unicorn_Platypus]

I use these food grade floating Polypropylene balls that someone recommended in another thread. They are pharmaceutical / food grade up to 230F

Been working really well as both a mash cap & lauter / whirlpool cap. DO numbers stay below 1ppm during mash, lauter, and whirlpool. No DMS & the hop aroma really gets locked in during the hopstands. They still allow for some evaporation, but not much

They add about 20 min of extra cleaning time, but I've gotten the hang of it. Its not as bad as it looks to deal with to scoop them out since they float to the top with water.

https://www.homebrewtalk.com/threads/diy-float-ball-for-sparge-water.524794/
The nice thing is they don't get in the way of any media I throw into the kettle like chillers, whirlpool arms, loc line etc.

 

[Bassman2003]

Ok Ladies and Gents, here's what I came up with...
I used my loc-line sparge circle and inverted it to the bottom of a SS lid.

View attachment 833020View attachment 833021View attachment 833022
With the nozzles pointed up, it'll deflect the flow and won't drill into the mash. Next is to add a seal which I think will just be something like 3/8 silicone hose with a slice to fit over the edge of the rim, glued on.

Does float? Seems like a large one.

 

[Red over White]

Ok Ladies and Gents, here's what I came up with...
I used my loc-line sparge circle and inverted it to the bottom of a SS lid.

View attachment 833020View attachment 833021View attachment 833022
With the nozzles pointed up, it'll deflect the flow and won't drill into the mash. Next is to add a seal which I think will just be something like 3/8 silicone hose with a slice to fit over the edge of the rim, glued on

Looks great, no need for a seal. It should move up and down freely. If you have some space like I do, accounting for it with some extra sulfites works splendidly.

 

[Bobo1898]

Martin is that material food grade though?

I believe locline is fine for recirculation and sparging temps. It's fairly common. Would be a shame if we've all been using it and slowly poisoning ourselves.

Does float? Seems like a large one.

While it looks great @DonT , I have the same question that @Bassman2003 has. I've been looking at kettle lids that fit my diameter as a mash cap, because I can't seem to find SS cake pans that are 13-14". Does it float?

Would also love to know if you have troube early in your mash with grain clogging the nozzles.

 

[Unicorn_Platypus]

I believe locline is fine for recirculation and sparging temps. It's fairly common. Would be a shame if we've all been using it and slowly poisoning ourselves.



While it looks great @DonT , I have the same question that @Bassman2003 has. I've been looking at kettle lids that fit my diameter as a mash cap, because I can't seem to find SS cake pans that are 13-14". Does it float?

Would also love to know if you have troube early in your mash with grain clogging the nozzles.

I wasn't questioning the loc line, I was questioning the foam

Locline is food grade and fine up to temperatures of 170F

 

[Bobo1898]

Ahh, I missed your quote. My bad.

Your question is valid, haha.

 

[DonT]

I have no idea if it floats... haven't got that far yet. The way I figure it, it won't need to float. It should sit on top of the grain itself as I usually have about an inch or so of wort above the grain bed.
When I had the loc-line sitting above and squirting down to the mash, grain would get in there and I would have to use a paper clip to ream out the nozzle that wasn't squirting. I may try to incorporate a filter somewhere in the line to prevent that, as I won't be able to see what's happening.

 

[Bassman2003]

The theory is that a mash cap needs to float to keep the surface from having contact with oxygen.

 

[DonT]

The theory is that a mash cap needs to float to keep the surface from having contact with oxygen.

It doesn't necessarily need to float, it just needs to seal out the air as much as possible.

 

[mabrungard]

Martin is that material food grade though? Would be my only concern about it

Needless to say, I fretted over that too. Its a foamed polypropylene material and the material is food safe.

 

[Unicorn_Platypus]

Needless to say, I fretted over that too. Its a foamed polypropylene material and the material is food safe.

Ahhh good to know!

My balls are polypropylene and also food safe! (that didn't come out right )

 

[Bassman2003]

It doesn't necessarily need to float, it just needs to seal out the air as much as possible.

Oxygen is a pesky adversary. It needs to float because that means zero "air gap" between the mash cap and the surface of your wort. Sealing out air also means some got sealed in! Yes, it needs to float to be useful for oxygen mitigation.

 

[skunkape]

OK. Time for today's DFQ...
Why the heck would I need to protect a mash from oxygen exposure when I'm oxygenating wort before the pitch anyhow? Somebody point me to the science here.

 

[Unicorn_Platypus]

OK. Time for today's DFQ...
Why the heck would I need to protect a mash from oxygen exposure when I'm oxygenating wort before the pitch anyhow? Somebody point me to the science here.

Oxidation staling reactions happen much quicker at higher temperatures (with the exception of boiling since O2 does not disolved in boiling water).

Active yeast scavenges oxygen and staling reactions occur much slower at pitching temperatures

If you oxygenate with active yeast in the wort, the yeast will scavenge oxygen more quickly than the oxygen can cause damage / staling. However, it's important that your yeast is active, so generally you would always want to pitch yeast from a starter for LoDo methods.

If you pitch directly from a packet the lag time might be too long and negate all the other steps you took on the hotside

 

[Bassman2003]

There are other threads where low oxygen is debated and rocks can be thrown.

 

[skunkape]

There are other threads where low oxygen is debated and rocks can be thrown.

No rocks here. I just never heard of limiting air exposure anywhere on the hot side and wanted to know what I was missing. Any process that potentially results in better beer is something I want to be aware of. I was a shameless secondary guy for a decade or so. That was just the way you brewed then. I eventually experimented with skipping secondary and closed transfers once I knew that was a thing. Definitely notice the difference with hoppy styles. Not so much on Belgians and Brits tho, which are my favorites. May not change a thing - but sometimes a man agotta do what a manna gotta do. Knowledge being power and all that.

 

[Bassman2003]

I and others are more than happy to lend knowledge and process' but we have to know it is safe to go in the water so to speak. Low oxygen brewing has had a rough go of it with many people downright rude over the concept. The science is there, it is just not easy to implement on the homebrew scale. The term alone sparks outrage with some homebrewers - "oxygen police" and whatnot. I (we) could care less how other people brew, just don't question something without doing the real world testing and research before one poo poo's it is our stance.

That said, in a nutshell. from the minute one grinds grain, just like when cutting an apple, oxygen starts to interact with compounds that alter the flavors. It is in the interest of a low oxygen brewer to try to limit this interaction as much as possible all the way until you pitch the yeast, which is when you add oxygen. It is a noticeable difference, especially in lagers and Belgian beers. If you want to learn more, just ask.