Thank you for posting that detailed evaluation. I’ve since spoken with the gentleman who built the device for me, and I now think I’ve been having a problem with leaks just as you did. Checking for leaks is on my to-do list, and I plan to revisit the … um, you know I still don’t have a good name for the darn thing.

I couldn’t see, in the photos of your CO2 acid test device, a way to correct for pressure inside the device. The CO2 acid test device I use has a movable reservoir, which you can see in the far left of the photo. Moving it up or down until the liquid in the reservoir is even with the liquid in the column indicates atmospheric pressure in the device. The idea is to take your initial and final readings at atmospheric pressure. If you don’t do this, then the final reading will be at a slightly higher pressure, and there may be some compression of the gas inside the device.

Interesting blog … I just ran across your post regarding measuring TA. I found a similar instrument a few years ago. It did not work very well. Here are some results that I found:
http://winefreeforall.blogspot.com/

Regards,

Jerrold