Whats going on here

When i do my mash i run off into a 2 qt measuring cup and add up how much i collect. But when add the amounts i collect from mash and sparge its always about a QT off of the stick i put in my kettle to measure. I checked the stick, made a new one and compared to the first they are exactly the same and i used the same measuring cup for everything. Would there be any reason for this?

What’s the diameter of the stick?

1/4 inch

Did you calibrate the stick at mash or room temp? Heat makes water expand.

I did it at room temp. Maybe im thinking of this wrong, but wouldnt that make the reading be higher not lower? Its coming up about a QT short in the kettle

So you’re measuring the wort as it comes out of the MT and then in the kettle you’re coming up short compared to what you measured going into the kettle or short for what you think should be in there based on a volume prediction (like in a brewing software app)?

First one. If i collected 6 gallons by adding up all the qts then checked in the kettle the stick shows its short by about a Qt. The first time i noticed it i figured it was just an error on my part or the stick was off. Its now the third time it happened. I checked the stick twice 1/2 gallon at a time with the same measuring use during the mash adn its right on. Makes to sense and its really bugging me.