Size of hydrometer cup

[nysap]

Just as the title of post states I have a question regarding the size of a hydro test cup to purchase. I have a 2x4 evaporator and this will be my first year with it. Was just ready to by some supplies and when I got to the test cup I see that in the small cup size there's a 1" or 2" diameter option. So what does every recommend? Thanks.

[morningstarfarm]

1" will work just fine...

[maple flats]

The larger holds the temp. much better, the small ones cool too fast and if you can't hold the temp your reading is not accurate. Even then, run syrup into the test cup and pour it back into the pot a few times to heat the cup and the hydrometer, then run your test.
I have made my own test cups in the past for a small fraction of what a cup costs. I made them out of 1.5" PVC pipe. I cut it to proper length, then I glued a flat cap on one end so it would stand up. I also used a second cap that had a rounded end and just slid it on as a cover when not in use. I eventually bought a SS cup in the larger diameter.

[johnpma]

My first 3 years I used a Stanley thermos as a hydrometer cup, I went to one of these stainless ones with the the finger ring last year. I agree it dissipates the heat quicker than my thermos did.......