Practice mashing. (Strike temp with RIMS)

[shuggie159]

I have a newish (modified) RIMS set-up and I want to practice my dough in / strike procedure which I have missed of late.

I was considering practicing with a grain equivalent. (copper fittings) and thought I would put my proposal to the collective intellect of the forum first.

As you'all realise the added complexity of the thermal mass of the heat exchange etc. complicate things a bit, so several dry runs make sense.

As much as I enjoyed phisics in the 1970's. I has become a little rusty. (Can't remember anything in fact)

If grain has a specific heat capacity of 1.84 J/gm.K and copper is 0.386 J/gm.K (please guys correct me, there is little info on SHC of grain)

For say a 4 kg grain bill, I substitute (4.00/1.84*0.38) 826 gms of copper fittings. Can it be as simple as that?

Many thanks

[PhilB]

Hi shuggie

I don't know what the SHC of grain is, but wrt the calculations (assuming the figures you have are correct, for now) ...

If grain has a specific heat capacity of 1.84 J/gm.K and copper is 0.386 J/gm.K (please guys correct me, there is little info on SHC of grain)
For say a 4 kg grain bill, I substitute (4.00/1.84*0.38) 826 gms of copper fittings. Can it be as simple as that?

... I don't think the sums are going to be any less simple, but I don't think that that's the right sum ... if it takes 1.84 Joules to raise 1 gram of grain by 1 Kelvin, and 0.386 Joules to do the same to 1 gram of copper ... then you're going to need more copper to mimic the thermal mass of your grain, not less ... 1.84/0.386 = 4.77 times as much to be precise ... then you'd have the situation you want with 1.84 Joules raising your 4.77 grams of copper by 1 Kelvin, to mimic your 1 gram of grain

... except that means you'll need more than 19kg of copper to mimic your 4kg of grain

Unless you run a plumber's merchants, I'd suggest you consider using something else ... maybe you could just "sacrifice" 4kg of grain to the cause ... or maybe "invest" 4kg of something similar but cheaper, like value/savers/smart price rice or pulses

Cheers, PhilB

[shuggie159]

Something must be wrong with the SHC of the grain. I'll try looking up rice, millet, and other dried goods to see if I can find anything similar.

I really wanted some other non perishable substance to mimic the grain, which I could do repeat runs with, to understand when/how the RIMS behaves.

[orlando]

I've no idea what you guys are talking about but I will make a comment about strike water. I use my RIMS to bring my strike water up to temp, this heats the thermo pot I have as a mash tun so by the time I'm ready to mash in it's perfect. You don't say how your RIMS is controlled so can't advise on that.

[shuggie159]

I too pre warm everything, using a sorta Vossy asparagus heat exchange.

The major problem Ive been having is that, despite throttling back on the solar pump, I've been having a problem with compacted mash bed restricting the flow. I recently up-graded to a thermo pot and was using a grain bag within for my filter. Doesn't work as a filter, but is much easier when it comes to the cleaning up. Obviously with the sensor in the out-flow pipe, the PIDS goes mental and I've had a few less than perfect mash's. I have now got a new filter and wanted to give it several trial runs, try alternative sensor positions, and hone my technique and get a feel of how the system should perform if the flow were un obstructed.

The SHC of the heat exchange slightly complicates matters because it makes the apparent Thermal capacity of the thermo pot much larger than it is.

Phil B You are very right. Copper has a very low SHC and it threw me. I cant afford that much copper!!!

Plan B I'm going to substitute 'water' since it has such a high SHC in lieu of 4 kg of grain I'm going to mash 4 X 1.84 / 4.181 = 1.76 litres of water in a bottle!

[Matt in Birdham]

I have a newish (modified) RIMS set-up and I want to practice my dough in / strike procedure which I have missed of late.

I was considering practicing with a grain equivalent. (copper fittings) and thought I would put my proposal to the collective intellect of the forum first.

As you'all realise the added complexity of the thermal mass of the heat exchange etc. complicate things a bit, so several dry runs make sense.

As much as I enjoyed phisics in the 1970's. I has become a little rusty. (Can't remember anything in fact)

If grain has a specific heat capacity of 1.84 J/gm.K and copper is 0.386 J/gm.K (please guys correct me, there is little info on SHC of grain)

For say a 4 kg grain bill, I substitute (4.00/1.84*0.38) 826 gms of copper fittings. Can it be as simple as that?

Many thanks

If you are using a RIMS, does it really matter if you hit your strike temp perfectly? I HERMS, and just set my water temp to my mash temp (usually), which results in a few degrees drop when I dough in. The HERMS brings it back up to temp pretty quickly, so I don't worry about it.

[Hogarth]

If you are using a RIMS, does it really matter if you hit your strike temp perfectly? I HERMS, and just set my water temp to my mash temp (usually), which results in a few degrees drop when I dough in. The HERMS brings it back up to temp pretty quickly, so I don't worry about it.

This. Though I have a standard strike water temp of 72°C, and use the HERMS to make any adjustment after mashing in. (EDIT: Though I suppose with a RIMS, you can't adjust down.)

[shuggie159]

Thanks Guys

Sorta got my head round it now.

The reason I seem uber concerned about dough in temp (strike), is because I believe with the modern malts the majority of the mash conversion happens far quicker than we realise. I'm of the opinion that most of the conversion is done in the first 20 mins. On that basis failing to spot the kick off temperature, and potentially damaging some of your target enzymes, will have an effect which cannot be recovered by achieving the perfect temperature later in your mash. Your sugar profile will have been predetermined.

I have found I have to continue doughing in / stiring for 4-5 mins to fully homogenize the grain / liqueur or you can easily get panicked by stray temperature readings and make un-necessary adjustments with cold water etc. Another reason to get confident of the strike process.

I have been advised with the RIMS best start low, only takes a couple of mins to get to target. But as Hogarth says 'with the RIMS you can't adjust the temperature down'

Sort of on topic - I record the mash temperature for each mash with a data-logger, so that I can at least try and identify what actually happened with my process, how and temperature profile effected the end result. They cost about £15 from China. 'Bloody Marvellous' as my old Dad used to say.

All of the above... and I'm not sure I brew better beer. Hopefully I just manage to brew good beer with confidence.

Cheers Guys

[orlando]

I suspect you are right about the first 20 minutes and the conversion has been mostly achieved, most not all. If right hitting and maintaining your desired mash temp as soon as possible is obviously desirable. What I still don't quite understand is how you are set up. You suggest the position of your probe isn't quite right and if that is immediately after exiting the Tun I'm not sure that's right, mine is placed after the heat source, which I think is the usual set up. You don't mention auto tuning, is that something your PID can do?

Although RIMS can't adjust down it actually doesn't have to, as soon as you start stirring the grains to knock out lumps and trying to get an even temp as quick as possible the goods will start to lose heat fairly quickly.

[Matt in Birdham]

True, but things are slower at lower temps, especially when you are out of the alpha range. Full conversion at beta temps still takes an hour or more. I full volume mash these days, and with, say, 32 litres of water and 6kg grain I only expect to lose 2-3C during mash-in (grain SHC isn't high), and that is quickly made up by the herms within a few minutes. Of course this all depends on your mash temp and grist ratio - things would be a little different if you wanted to mash very high with a thicker grist.

[Hogarth]

things would be a little different if you wanted to mash very high with a thicker grist.

Exactly what I tried to do today ... and got a mash temp of 62°C That'll teach me to be so blasé about mashing-in with a HERMS.

[Fil]

i guess you could do the maths and it will probably lead you to a close to optimal strike temp,

but you will need to factor in all the radiant surfaces and what they are made of too. probably a lot easier to set the strike temp to 71c heat up and recirculate to bring the liquor and equipment upt temp, mash on your grain and read the temp . then if necessary adjust with a jug of cold water or some off the boil water, till your at the optimum mash temp. and knock back or up the strke temp accordingly based on the experience..

[orlando]

i guess you could do the maths and it will probably lead you to a close to optimal strike temp,

but you will need to factor in all the radiant surfaces and what they are made of too. probably a lot easier to set the strike temp to 71c heat up and recirculate to bring the liquor and equipment upt temp, mash on your grain and read the temp . then if necessary adjust with a jug of cold water or some off the boil water, till your at the optimum mash temp. and knock back or up the strke temp accordingly based on the experience..

Beersmith will do all that for you, it asks you what type of kit you are using so it can adjust strike temp to account for the materials your equipment is made of.