Equipment for checking temperature of caramel inside the tank?

We have three large tanks that we use to heat and mix our caramel. Using the settings on the tanks, our caramel is usually perfect, but we don't have any data to log for quality. If it is mixed right and set right, the caramel looks right, we use it. We have recently started talking about quality checks and would like to somehow come up with a temperature range for the caramel so we know we are using quality caramel in our product every time. What equipment might be best to used to check the temperature of the caramel inside the tank? The tank itself is about 4ft tall. Testing from the top of the tank is a simple probe thermometer would be inaccurate. 

Hello,

There are some thermometers with long probes that can reach the 4ft you need. Something like this ( https://www.webersci...mperature-probe )

And also i would recommend for you to keep a log of the temperature from near the bottom of the tank and near the top.

will an infra red thermometer work for this application?

You could have thermometers mounted through the tanks (and then sealed of course) that could be right in the middle, then you never have to probe again, just read the display