This weekend, I forgot to take a reading on my extract (to determine efficiency). I finally remembered when it was well on its way to boiling. I opened the valve and filled the hydrometer jar - mine is plastic. I set it aside to cool, leaning it in a corner of the window sill.
Well, when I went to take a reading, the thing had more than a slight curve to it. The hydrometer still moves freely in the jar, but I am concerned that there is too much contact with the sides.
Anyone found something readily available that works well as a hydrometer jar?