Hlt Thermostat

[wedge]

Right, i've finally got my ass into gear to get a HLT. I have been mashing using only one keg for 18 months now.

So i'm looking at sourcing a keg, placing in a 2400kw element and a 'Mashmaster Thermostat'.

What i have noticed is that alot of the HLT pictures on this site show the probe from the thermostat pretty damn close to the element.

I was hoping to cutdown on my brew day. ie Start the day with my mash water already ready, but if the probe is too close to the element it may give a reading that is not true. As in the bottom is 66C but the top of the water is only 30C. ??

The ideal method ofcourse it to have some sort of automated stirer. Thats too flash for me.

Any ideas. Or is the difference really negligable.

What height should the probe got. I only do 23l batched

 

[Wortgames]

Well you'll get a bit of turbulence every time the heater element switches on, which will mix the water up, so you shouldn't get too much stratification whenever there's a thermostat involved. If it's too close to the element though you will probably find that it cuts out pretty quickly and spends more time off than on.

I have a controller mounted in a separate box, and just dangle the probe into the HLT about half way. I figure this gives me a fair average reading.

The other advantage of this is that between brewdays (ie, most of the time), you can use the same temperature controller on a fridge for fermenting.

 

[wedge]

Stratification ... thats the word i was looking for.

I guess if i mount it say at the 10 litre mark that should leave things working well.

 

[lonte]

It doesn't seem to make that much difference in my set up where the probe is. I have a timer and thermostat set up - before i read the temp I give the water a good stir and find I'm usually with +/-3*C of strike temp. I then adjust the thermostat up or down and by the time I've made a cuppa and got everything ready the water is right at strike temp.

 

[Wortgames]

Stratification mostly occurs when there's no other movement in the liquid - the hotter water will rise to the top, and could be quite a bit hotter than the bottom. As soon as the element switches on though it will create turbulence as the freshly heated water makes for the top.

If you were using the water a little bit at a time, then it would probably make sense to put the probe closer to the outlet, so that the water you take is at the precise temperature you want it. If you are wanting to heat a batch of water for use all at the same time though (like us brewers), I reckon it makes more sense to have the probe somewhere in the middle, which is probably the best indication of your average temperature.

 

[Screwtop]

What ever happened to physics and the Archimedes principle, doesn't it apply in brewing and HLT's? Used to be that temperature had an effect upon gases and liquids. Hot water has more "kinetic energy" which in turn makes the atoms take up more space and therfore makes it less dense and lighter so it will rise. A little uneveness in temp distribution will always occur, just a little stir before checking the final temp is all thats required.

 

[wedge]

LOL. Archimedes was having a bath, not brewing beer

 

[Wortgames]

What ever happened to physics and the Archimedes principle, doesn't it apply in brewing and HLT's? Used to be that temperature had an effect upon gases and liquids. Hot water has more "kinetic energy" which in turn makes the atoms take up more space and therfore makes it less dense and lighter so it will rise. A little uneveness in temp distribution will always occur, just a little stir before checking the final temp is all thats required.

Isn't that what I said, albeit in different words? :blink:

The point is that if you are using a temp controller, you are 'continuously' checking the temp - hence you would need to be 'continuously' giving it a little stir. That's why I suggested having your probe somewhere in the middle, where you should be getting a good average temp of the entire volume.

 

[wedge]

Thanks guys for the help. I will be putting in in the middle.

 

[kook]

I recently built an electronically controlled HLT and I have the element and probe rather close to each other.

So far, what I have found is that all water above the element is consistent in temperature. I presume this is due to the steam bubbles that rise off the element, as they do move the water a little.

All the water below the element however, stays cold. I've considered a stirrer, but it seems like overkill to me. Instead I just wait for the main body of water to come to temperature, then give it a stir. I find this drops the temp by 2-4 degrees the first stir. Once it's at temp again, I stir again. After that point the water temperature seems to remain reasonably constant. I still plan to insulate the HLT though, in particular the base.

 

[Goat]

Kook - can't you re-circulate via your pump? That way you de-stratify the water AND you pre-heat the pipework

 

[wedge]

Thats a bloody good idea Goat. I should have thought of that.

Like i said te idea is such that the HLT is heating up as im having breakfast, so that i can reduce my brew time.

Ill just schedule to turn it on when the HLT turns on and just keep recycling the water.

The only negative is - chewing electricity and ofcourse the loss of heat. I will just have to insulate my lines as well as the HLT


Cheers again

 

[kook]

Goat, I could, but to be honest I don't think it's necessary. I might try it next time at the point I would normally stir.

I don't bother pre-heating my piping, as i'm only using a very short run of silicone from my HLT to the MLT via gravity.

 

[Batz]

I have an old windscreen wiper motor working as a stirrer,if I use the element for say 40min,then start the stirrer the temperture drops heaps.I believe it's needed for a uniform temperture.

Batz

 

[AndrewQLD]

I agree with Batz, my temp fluctuates from cool on the bottom to hot up top and usually requires several good stirs over a 15 minute period to get a uniform temp from top to bottom. A mechanical stirrer would help heaps.

Cheers
Andrew

 

[Jye]

Kook - can't you re-circulate via your pump? That way you de-stratify the water AND you pre-heat the pipework

This is what I do.

wedge check out this thread and the last post, this is the inlet on top of my HLT (same as my kettle), you could place the thermostat where the thermometer is. I like the idea of having the thermometer at the end of the hose because this will give the exact read of the water temp going into the mash tun.

 

[redbeard]

In my HLT setup, I usually crush the grain while the HLT is heating up. When the temp is about 5 or 10' to final, i draw off about 5l, which is about the deadspace under the element, & just tip into the top, where it mixes in. I then measure the temp in the tun when underletting, but have a good feel for the final hlt temp now

cheers

 

[Screwtop]

I recently built an electronically controlled HLT and I have the element and probe rather close to each other.

So far, what I have found is that all water above the element is consistent in temperature. I presume this is due to the steam bubbles that rise off the element, as they do move the water a little.

All the water below the element however, stays cold. I've considered a stirrer, but it seems like overkill to me. Instead I just wait for the main body of water to come to temperature, then give it a stir. I find this drops the temp by 2-4 degrees the first stir. Once it's at temp again, I stir again. After that point the water temperature seems to remain reasonably constant. I still plan to insulate the HLT though, in particular the base.

Spot on with the above. Stratification occurs because of a completely different set of circumstances, like in a deep still body of water. It's a physical impossibility for warmed water to rise without it being replaced, so it moves around, just a little stir once the thermostat switches off is all thats required. If you are going to stir your water, it doesn't matter where you place the thermometer.