Microwave RIM system

I admire your inginuity but I am missing something that may have been earlier in the thread, but if it was I've missed it. My question is, why would you want to take this route rather than a more conventional RIMS or HERMS?

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I am looking for something to do step mashes with a cooler based mash vessel. I want my mashes to be as traditional as possible, ie the least amount of pumping and the gentlest heating. With a well insulated cooler, one should only have to add heat once in a while to maintain temp and other than that just boost it periodically as per the schedule.

The problem with RIMS (ie a heater element heating circulating wort) is wort scorching, especially if the recirculating flow isn't high. In order to avoid wort scorching, one has to get the power density down to less than 10 watts/in^2, as far as I can tell.

The problem with a conventional HERMs system (heat exchanger in the HLT) is that:

a) the HLT water has a lot of mass, so its hard to quickly change its temperature for step mashes

b) One really needs 2 pumps or at least a pump and a stirrer. One pump circulates the wort and the other device moves the water in the HLT. If the water in the HLT isn't moving the heat exchange is poor.

HERM systems work, but its a slow responding system. People have gotten around this by using a very small dedicated heating tank, but now we are talking another vessel, heating element, etc.

So, I am proposing 2 new ways of heating the mash.

The first method is the steam injection system. This is theoretically a non circulating system ! The mash might be stirred occasionally and probably as the steam is being added, but the heat goes to the mash rather than the wort to the heater. I've got my boiler built and pressure tested. I'll be generating test steam one of these days when I get time.

The other method is the microwave RIMS system. What I like about it is that we have full control over the microwave power output, there is no scorching of the wort, the temperature response should be fast, I don't have to put a heat exchange coil in my HLT, etc. Its a pretty simple system.

"Well, if I attempt this it will really be a preheater for my boils. After reading the thread on using the tankless water heater this sounds like a viable alternative the that."

Yeah, it should be. I wonder if the tankless hot water heater would scorch the wort. Generally heating elements for water are fairly high watt/in^2.

"Does that sound like a good idea to you guys?"

As far as a preheater for the boil, a microwave doesn't output much power compared to a burner. 1300 watts is only 4435 btu per hour. If your sparge took 30 minutes and drained 6 gallons (50 pounds), it would only raise the temp of the wort by 44 degrees. (From 170 to 214F.) I mean it helps, but its not a powerhouse in that regard.

I see it more as a means to gently heat recirculating wort. It could work really well for doing 5 gallon step batches in a cooler.

Truthfully, I am thinking the steam generator is going to work really well and I might not test the microwave heater. But if I was only interested in 5 gallon batches, I think I would be using it.

brewman ! said:

HERM systems work, but its a slow responding system. People have gotten around this by using a very small dedicated heating tank, but now we are talking another vessel, heating element, etc.

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This is the way I've done it. I built a 2 litre copper container with a kettle element in one end and a small coil in the other to recirculate through. The element is controlled by a PID controller that senses the temperature of the wort exiting the copper coil.

The whole thing has cost me around $100. It really is a very simple solution to the problem you mentioned with traditional HERMS.

I personally would not be comfortable working with high pressure steam or modified microwave solutions. But, it would be great if you could get something working that doesn't denature the enzymes or endanger the operator.

I hope your trials go well with the steam solution.

All the best,
/Phil.

Have you considered direct steam injection to circulating wort as in a rims system instead of trying to inject the steam into the mash directly. Here is a device i have copied and used with my R&D system.http://www.pickheaters.com/nav_2.cfm

You could easily inject the steam into the circulating wort. Just Tee into the circulation line and use a check valve to prevent any possible backflow into the steam keg. No problem there.

Now that you mention that, I might try it. One less hole to make in the mash vessel and then one doesn't have to worry about hot spots with the design of the steam distribution manifold at the bottom of the mash vessel. And I would recirculate the wort a bit anyway.

However, one of the things I like about adding steam to the mash vessel is that the mash can just sit there and cook with the odd stir. Versus with a HERM or RIM system where the pump seems to run quite a bit of the time. Although it wouldn't have to if the vessels were insulated as well as a cooler mash vessel.

Rightly or wrongly, I am trying to mash my grains by having them just sit there, like a bowl of oatmeal, giving them the odd stir to keep the temperature even and the mix up the grains. Circulating the wort a lot seems unnatural to me, like it wouldn't be what we would do if we were making oatmeal. I know that it is probably OK if one is watching for HSA, but still there is something intuitive to have the grain just sit there and mash versus having wort continually cycling through the bed. Maybe its just me.

In the winter I make oatmeal every morning in the microwave. I make it with milk and bring it to a boil and then let it sit for 20 to 30 minutes with a lid on the container. I am tempted to get some iodine and see how my starch conversion is !

Consider this approach, build a water heater/steam generator that feeds the wort mixer with the abilty to operate in 3 modes. Fist mode would be strike water heater for filling mashtun, second mode would be to generate steam for wort mixer for step mashing, and third mode would be to heat sparge water for fly sparging. Control of the 3 modes is by water flow through heater and control of heat source to hit temperature. For safety purposes there would only be a check valve between the water heater/steam generator and mixer to prevent pressure buildup beyond back pressure of mixer.

My setup is going to have an HLT and a steam generator. I am undecided if the HLT is going to be electrically heated or by an electronically controlled propane burner. So heating the strike water and heating the sparge water will be a no brainer.

The steam boiler will only be used for maintaining the temp of the mash and boosting the temp for steps are sparging.

I guess you could use the steam boiler for the source of the strike water and sparge water *with careful mixing and such* but its just easier to have a separate vessel (ie HLT) with its own control system keeping the water at the right temp.

Ideally, this is how I would like a brewing session should go.

Night before: roll out the brew stand. Put water in the HLT and steam boiler. Put the grain in the mash vessel. Plug everything in.

6AM, warm up. WHILE I AM SLEEPING, the heaters in the steam boiler and the HLT come on and get the contents up to temp. For the boiler, that is 240F, for the HLT, about 145F or so.

8AM, mash in. I pump 1.25 quarts per pound of water from the HLT into the mash vessel and stir it. I'm probably aiming for 135F. Once its thoroughly mixed, I go to my laptop and put the mash vessel temp control on auto with a setpoint of 135F. This allows the computer to open the steam valve when necessary to keep the mash at 135F.

I move the temp setpoint for the HLT to mashout/sparge temp, 172F.

I go have my morning coffee.

8:30AM, starch conversion temp step. The computer moves the mash temp setpoint to 154F. This causes the controller to open the steam valve and inject steam into the mash, until it hits 154F. Ideally I am there stirring the mash a bit.

9:30AM Sparging temp step. The computer moves the mash temp setpoint to 170F. This causes the controller to open the steam valve and inject steam into the mash until it hits 170F. The pump is hooked up to circulate the wort and clarify it for a few minutes.

9:45AM Sparge out. Automatic mash temp control is turned off. The pump is hooked up to pump water from the HLT (now at 172F) to the mash bed such that it keeps about an inch of water over the bed. This is controlled by a level switch in the top of the HLT. I adjust the valve on the bottom of the mash vessel so that the wort drains into the boil kettle at a rate of 1/6 gallon per minute. (Sparging takes 36 minutes for 6 gallons.)

I start the boil kettle burner once a few gallons of wort collects in the kettle. If I want to speed this up, I can dump the leftover steam from the boiler into the kettle.

10:15 Boiling starts. I'm adding hops, cleaning up the mash vessel, getting the fermentor sanitized, etc. (Sparging will continue until 10:22AM)

If I am brewing 2 batches back to back with a friend, here is where I will dump the mash vessel (it will be on a tippy) and mash in the second batch, using a combination of leftover HLT sparge water and cold water. I only have to get it close and the steam boiler will bring it up to temp. Actually, we have our house hot water set at 120F, and that is probably close enough for the steam boiler to bring it up to temp.

11:15 I hook the pump up to the boil kettle outlet and circulate boiling wort through the CFC back into the boil kettle. This sanitizes it.

11:30 The boil is done. I turn the cold water on for the CFC. After a few minutes I stop pumping back into the boil kettle and start pumping into the fermentation vessel.

If we are doing a second batch, the mash temp moves from 135 to 154F here.

I direct the hot water out of the CFC into the mashvessel and the now empty HLT to be used for cleaning. When I am done cooling the wort, I have the HLT, mash vessel and steam boiler all full of hot water for cleaning.

11:45 The fermentor is full and capped. I oxygenate for a bit and pitch the yeast.

I dump some of that hot water from the mash vessel into the boil kettle to rinse and clean it with. I circulate clean water from the HLT through the CFC to clean it.

I start putting things away.

Noon. I roll my brewstand into the corner until next week. I'm done ! (If we are doing a single batch.)

12:30 Second batch is heated for mash out.

12:45 Second batch sparge starts

1:20 Second batch boiling is underway.

2:30 Second batch boiling is done, CFC sterilization starts.

3:00 2nd Fermentor is full. Cleanup starts.

3:30 All done with second batch.