HERMS and Mash Tun temperatures

I have upgraded from a cool box mash tun to a thermopot, and I have a daft question on mash tun temperatures.

I have a 5L S/S HEX pot fitted with a kettle element controlled by a PID. I monitor both the exit temperature of the HEX and the output from the mash tun. The pump recirculates the wort between the HEX, and returns it to the top of the mash tun.

The temperature differential between the mash tun and the HEX was only 0.2 degrees C using the rectangular cool box, as the grain bed was relatively thin. Now using the thermo pot the grain bed is considerably greater than the cool box.

The temperature differential is now 1.5 degrees C.

Today on a brew, I set the HEX output to be 67 degrees, (I wanted to mash a little higher on this particular beer). The output from the mash was 65.5 degrees C.

Question: If wanting a higher mash temperature, ie 67 degrees C. Do I use the output of the mash tun for this?

If so, then the HEX temperature would need to be around 68.5 degrees C for the grain bed to see it at the exit of the mash tun.

Which is the most important temperature to monitor in this situation, the HEX output, or the mash tun

Any advice from the more experienced HERMS brewers would be most appreciated.

Best regards,
WM7793

HEX Output always . . . Insulate your returns . . . . . In fact insulate ALL your pipework . and keep the lid on the thermopot

It will take a little while on recirc for the output of the tun to be at mash temp

Thank you Aleman, for your advice.

I have not insulated the pipework, that is a great idea to maintain temperatures.

One final question:

How do you secure the hoses to the camlocks, do you use jubilee clips, or something else.

Best regards,
WM7793

I use oeticker clamps . . . Much better than jubilee clips . . . But permanent!

I found that shortening the pipe helped. We use silicone hose for the connections between herms and thermopot and they are very close together. Also the herms return in the mash tun runs through a perspex disk which helps minimise losses. Last time i took the temp from the liquor from the mash tun it was the same as the output from the hex

Many thanks Aleman and Mark1964, for your excellent advice. Will check out these oeticker clamps!

Best regards,
WM7793

I use these.

http://www.ebay.co.uk/itm/Set-of-10pc-J ... xyBvZTR8cl

Cheap and cheerful!
If it breaks, just replace it.

I have been using Jubilee clips, but I found that they were not as secure as I would have liked, in the sense that they were allowing some air get into the HERMS system and causing a reduction in the flow of the pump.

Also the clips have a tendency to tear the silicon hose a little, when nipping these down to try to eliminate the air bubbles getting into the system

I do like the look of these oeticker clamps.

Best regards,
WM7793

i changed the barbed hosetails on our pots to 15mm chrome piping and the silicone hose fits nice on them so does away with any clips

Hi Mark, I also removed the hosetail barbs and spashed out on camlocks. Getting a good seal on the hose with the camlock connector, is the main problem, which is allowing small quantities of air into the system and in turn reducing the flow from the HERMS pump to the mash tun.

I am going to wait and upgrade my "type 2 12v DC mag pump", to a "chugger". Rearrange the hoses to suit, then try the oeticker clamps early next year.

Best regards,
WM7793

Forgot to mention.
I am currently waiting for delivery of 16mm stainless steel coiled pipe for my 5L HERMS pot. I built it originally using 10mm copper, but I was looking to eventually replace the copper coil with stainless. I eventually found a company who would custom build one for me. I have also found a supplier who offers 16mm to 1/2" BSP compression fittings. (The supplier of the stainless steel coil could not supply 15mm coil, so I had to go another route)

Will be interesting to see what it looks like, and how it performs when it is installed.

Best regards,
WM7793

Mark1964, great idea to add the 15mm pipe,
Also forgot to mention this as well!!

Best regards,
WM7793

use short lengths of 15mm copper or ldpe tube friction fitted into 1/2" thick walled silicone hose and then JG fittings for a semi quick release option good for a minimum of 15-20 on/offs on paper, quite a few more in my experience the added bonus is they rotate easily too

Hi PhatFil, some great ideas coming in!

Beset regards,
WM7793