Sunday, January 16, 2011

Thrumometer Upgrade

I've been wanting to add this tool to my arsenal of brewing gadgets for a long time. In the past, in order to monitor the temperature of the wort going into the fermentor, I've been sticking a thermometer in the stream of the wort as it runs out the end of the transfer line. Depending on the temperature I would slow down or speed up the pump that pushed the hot wort though the plate chiller and my post chiller chilling coil. (Go here to see the post chiller set-up I use that gets the wort down to lager temps). This has worked fine but is awkward to handle and a possible source of bacterial contamination. With this new in-line thermometer I can relax a little more during this crucial stage of the brewing process.

Notice that the Thrumometer's lowest temperature is 58f.

Naturally, I had to make a minor modification to the Blichmann's Thrumometer because of a serious limitation. The manufacturer of this fine tool did not provide the temperature reading range needed to register temperatures down in the lager range (46f.-58f) which could be easily Incorporated during manufacturing. And because now is the time of year for brewing lagers, I need to insure that the wort temperature is going to be in the low 50's. What to do?

Using scissors, cut out the section that contains the lager temps.

The solution: simply applying the lager portion of the Fermometer to the opposite side of the instrument using it's self adhesive backing. For those unfamiliar with the Fermometer, this is a self adhesive liquid crystal display thermometer that is typically adhered to the side of a carboy or similar fermentor and measures temperature by contact with the vessel.
The adhesive backing is strong and initially it seems to be adequate to hold the new thermometer strip in place but I'm concerned that over the course of several brewing sessions and in contact with the wet environment that the glue will fail. I don't show it here but I plan to cover the new thermometer with a layer of strong, clear tape to insure that it stays put for awhile.

Using the self adhesive backing, adhere fermometer to the device

Once the new correction was in place I inserted the Thrumometer in-line in the transfer hose and will put it to the test tomorrow when I brew my pale ale. I'm also going to forward this post to the good people at Blichmann engineering to suggest this valuable upgrade idea.

Modified Thrumometer in line

Does anyone else use this device, what's your experience and have you had to modify it like I did here?

1 comment:

Anonymous said...


I have been using this devise for several years with good success in the same way you are setting up yours. I would like to know how your modification works out. I may do the same with mine if you are successful.


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