I was thinking about this again. If the stand pipe is just protection from a stuck mash/ pump running dry. A stand pipe could be built to the side of the kettle, if someone wanted to use a bag instead. Bag may not give the same flow through when recirculating, but a few stirs could do the trick if someone was trying to do this on a tighter budget.
Good idea. You could get a pieces of SS, aluminum or plastic triangle or U shape of the various lengths and put one the right length between the bag and the kettle wall. Bingo, you've got a route for excess liquid to get down to the kettle element if the mash sticks.
You can obviously start brewing with a bag and add the grain basket later on too. I used an elcheapo boil kettle from my LHBS. You can also buy a replacement grain basket from a Robobrew. They aren't that expensive.
The grain basket isn't getting heat applied directly to it, so it doesn't have to be thick or anything. And it doesn't have to be insulated. And it doesn't need a valve. In fact, you could use a food safe plastic bucket. Drill holes in the bottom to act as the false bottom. Hang it from the boil kettle with a stick and some wire. Or set it on some pieced of aluminum in the boil kettle.
In the old homebrewing days, we used to make mash tuns by putting one plastic bucket inside another and drilling the inside bucket to make the false bottom. (See Dave Miller The Complete Handbook of Home Brewing, 1988) BTW, I did my first ever full boil in a plastic bucket with a heat stick. It works.
I didn't understand the want/need for a standpipe either until I read this thread and noted the trouble they had with stuck sparges and efficiency when they didn't get the grind right.
https://www.homebrewtalk.com/forum/...o-from-co-brewing.575659/page-37#post-8506017
In fact, I asked why it was even used.
https://www.homebrewtalk.com/forum/...tandpipe-and-mash-screen.599106/#post-7841472
The standpipe is actually ingenious.
First it prevents a big vacuum from forming under the mash. I didn't understand that actually happening until I ran Thing1 and saw the difference in water level between outside the mash cylinder and the water at the top of the mash bucket, when I am running without a stand pipe. That differential head is the suction that the pump is putting on the grain bed. WOW. That suction collapses the grain bed tighter and further restricts flow. Which increases suction. Which restricts flow... until the bed gets stuck if it gets too bad.
So I'm guessing that a grain bed with a stand pipe flows quite a bit more than a bed without a standpipe because there is no suction acting on a bed compressing the grains with a standpipe.
You can take this one step further like the Braumeister does and flow through the bed backwards, from bottom to top. That bed will never stick and will flow much more than if it was top to bottom. There is actually an engineering term for a bed like that, it is called a "fluidized bed" because the bed particles (grain in this case) are actually "floated" by the fluid.
I thought about building a system with a reverse flowing bed but didn't like that the volume of water used in those systems is pretty much constant (because the height of the mash cylinder is fixed) thus you don't have control of the mash/water ratio, ie mash thickness.
Just to put some numbers to this suction thing, 27 inches of water is 1 PSI. Wort has a higher density than water, so maybe 24 inches of wort = 1 PSI. (Guessing here, could calculate it, I'm too lazy.)
So if the grain bed has 6 inches of suction on it, that is 1/4 PSI. Doesn't sound like much except a 12" diameter bed is 113 in^2. 1/4 PSI on that bed is 28 pounds of force pulling the grain particles closer together.
The second thing the standpipe does is allow a much faster recirculation rate. With my old HERMs getting the grain bed to warm up quickly was always a problem because the flow through the bed limited how many BTUs you could extract from the HERMS coil. Big grain bill = deep bed = slow flow = limited BTUs = slow heat up. But with a stand pipe you can run the pump full flow and the excess goes down the stand pipe. That means there is always lots of fluid moving past the heating element and the mash temp is never heating limited, it is always flow limited. And with a non suctioned mash bed the flow is better too. So I'm guessing that a mash with a standpipe will heat up much, much faster.
The 3rd thing about a standpipe mash is that if you set up the standpipe correctly, you can walk away and not worry about the grain bed flow going awry. The pump will never suction the bed into sticking. The element will never run dry. The heat flow will always be fine. The big design goal for me with Thing1 was unattended brewing and a stand pipe helps that happen.
There are 2 other things I like about using the mash bucket.
1) There is a water reservoir between the mash bucket and the boil kettle wall. This volume is insurance against the heating element running dry. The pump would have to completely suck that volume out before the element runs dry.
This is part of making the stand pipe work well. A stand pipe without a volume of water between the mash and the kettle is better than nothing but there is no additional fluids to draw on to make the stand pipe overflow like there is with the mash bucket inside the boil kettle.
But obviously that volume also messes with the mash thickness too.
2) The grain doesn't sit against the wall of the boil kettle. The grain bucket is surrounded by water which is presumably at mash temp or maybe even a bit higher. In fact, heat can be conducted into the mash through the walls of the mash bucket instead of it being lost to the walls of the mash tun.
FYI... it is pretty easy to apply heat in difficult places with induction heating. One could wind a coil around the perimeter of a vessel and heat the walls of the vessel too. This would mimic the steam heat jacket that is used in commercial breweries. Our small vessels have small volume to surface area ratios, so we don't really need to do this. But it is still an option.
The "Thing1" looks rad. The only thing I would change would be to replace, paint, or seal the plywood top (for personal aesthetic preferences).
I don't like that plywood either. That plywood is actually a test piece because it is hard to find a material that isn't ferromagnetic, doesn't conduct electricity and stands up to the heat that occurs between the induction coil and the boil kettle.
Induction cooktops use a type of ceramic glass. It turns out to be a special glass. I haven't found a source for that glass, nor can that glass be cut after it is manufactured.
I tried high temperature plastic and experienced a meltdown. The fiberglass that holds the induction coil to the underside of the plywood base would also be a good material, but I can't get it without buying a full sheet and it is somewhat expensive.
BTW, there is a layer of insulating silicone pad between the induction coil and the plywood.
Glad you've been able to fit brewing into the family life. It gives me hope.
I'm glad this might have given you some ideas.
I'm still testing that, but it appears Thing1 will make it way more viable. The fact I can mill the grain, get everything out and set up and have the mash water up to temp before the actual brew day starts makes a big difference in the time block I need to set aside to do a brew.
I can mill my grain a day or more before and have Thing1 rolled into the corner of the kitchen ready to go. Before I go to sleep or work I roll Thing1 up and plug it in and put in the water. I start heating the mash water before I wake up or get home. When I get to the kitchen all ll I have to do is mash in and adjust the flow and I can then walk away and leave it run the mash unattended for 60 minutes or more. It doesn't require constant attention like my old brew rig did.
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