Gravity reading issue

[timboslice1982]

I brewed an all grain pumpkin ale this weekend and had some issues measuring the extraction gravity. After pouring the wort into the boil kettle, I pulled a sample into a glass to let it cool before taking a hydrometer reading. When the sample had cooled to approximately 75-80 degrees, I testing the sample with my hydrometer and got 1.042. Because I had plenty of wort left to do a second check later, I set the glass inside and let the wort cool further. A second read (about two hours later) was 1.036. Why would I get a different reading from the same sample, the only difference is letting it sit and cool another 5-10 degrees? (A later reading from a refractometer was 11 Brix, which translates to 1.044)

I used the same hydrometer for both readings and same source sample for all three readings (2 hydro, 1 refrac)

 

[tootal]

Hydrometers are set at either 60 degrees or 68 for the newer ones. Temperature affects the gravity so it will change. Look on your hydrometer, it will say what temperature it's calibrated to. As far as getting a lower reading with cooler wort is the opposite of what should happen. Find out what temp you should be and get your wort to that temp and then take a reading.