Steam Injected Mash System - Page 7

brewman ! · 03-26-2007, 05:16 AM

I might have confused you when I said you have to consider the phase change because it wasn't clear to me if you were talking about making steam at 240F or making hot water at 240F. If you are doing things like me, you are making hot water at 240F. It converts to steam at 212 F when the valve is opened.

brewman ! · 03-26-2007, 05:17 AM

What are you going to use for a vessel ?

**Yuri_Rage** · 03-26-2007, 05:17 AM

Quote:

Originally Posted by brewman !

I might have confused you when I said you have to consider the phase change because it wasn't clear to me if you were talking about making steam at 240F or making hot water at 240F. If you are doing things like me, you are making hot water at 240F. It converts to steam at 212 F when the valve is opened.

Exactly! All this talk of heating steam isn't really necessary - that's not what we're doing! (for the most part)

Quote:

Originally Posted by brewman !

Right, at 240F. But we *ARE* making steam at 212 when the valve is opened. But one doesn't really need to calculate that because the equilibrium situation after all the steam has blown of will be hot water at 212F.

Got it! That was a lot of typing tonight for a rather simple concept in the end. Hope I didn't confuse anyone more than I did myself.

brewman ! · 03-26-2007, 05:20 AM

Right, at 240F. But we *ARE* making steam at 212 when the valve is opened. But one doesn't really need to calculate that because the equilibrium situation after all the steam has blown of will be hot water at 212F.

**Yuri_Rage** · 03-26-2007, 05:20 AM

Quote:

Originally Posted by brewman !

What are you going to use for a vessel ?

I have some single handle corny kegs that should work nicely. I can TIG weld, wire, sweat pipe, etc, etc. I'll be sure to use a pressure relief valve in the system. All of the cutting and welding will be in the lid of the keg where I'll least affect the structural integrity of it.

brewman ! · 03-26-2007, 05:23 AM

This statement "the hard part is adding another 970 BTU's/lb to make steam at 212 deg F" gives us a clue as to how much steam we are actually making. In K's example, we needed 1026 BTUs to heat the mash. At 970 BTU per pound, that's only a bit more than *ONE* pound of steam. So what happens is our 240F hot water flashes off to steam until it reaches equilibrium at 212F, in the process making a pound or so of steam. The rest of the 5 gallons, 40ish pounds, stays as hot water.

brewman ! · 03-26-2007, 05:25 AM

Quote:

I have some single handle corny kegs that should work nicely. I can TIG weld, wire, sweat pipe, etc, etc. I'll be sure to use a pressure relief valve in the system. All of the cutting and welding will be in the lid of the keg where I'll least affect the structural integrity of it.

Pressure test with cold water (NOT AIR) to 3x the working pressure of your vessel (15x3 = 45 PSI) and don't apply a direct flame to the vessel. Make sure the pressure relief works under all conditions too.

**Yuri_Rage** · 03-26-2007, 05:27 AM

Quote:

Originally Posted by brewman !

This statement "the hard part is adding another 970 BTU's/lb to make steam at 212 deg F" gives us a clue as to how much steam we are actually making.

I finally wrapped my brain around that as well. I was thinking of it completely backwards when I first read the post (as in, I have to add that much energy to the existing super-hot water after I vent some steam). Now I understand that if we were only making steam at 212 degrees, it would take a TON of energy to vent enough into the mash to make a difference. Fortunately, the "pressure cooker" effect is on our side.

brewman ! · 03-26-2007, 05:33 AM

Right ! It does take a bit to get ones head around it.

40 pounds of STEAM (not hot water) at 240F and just under 15PSI would take a huge vessel ! Steam is very light.

[quote]Now I understand that if we were only making steam at 212 degrees, it would take a TON of energy to vent enough into the mash to make a difference[quote]

It would actually take the same energy either way. It would take a ton of energy PER POUND, but the number of pounds would be small, like a little over one pound.

The reason one uses hot water like that is so the vessel stores as much energy as it can so when you open the valve everything heats up quickly.

When I open the valve on my pressure cooker, the steam comes out of the hose like air out of an air hose. Steam is very light. And it stays as a gas (vapor) well into the mash. It bubbles the mash pretty good.

**Yuri_Rage** · 03-26-2007, 05:34 AM

Awesome. It's bedtime. Thanks for the patience.