Calculating Efficiency
 

I have read Palmers take on calculating your mash efficiency and am left with a question. When I take a hydrometer reading of the wort collected pre-boil, do I need to convert that number based on temperature? I measured my OG to be 1.032 pre-boil for six gallons at approximately 150 degrees F. Thanks!

It doesn't matter what the purpose of the reading is, you must always compensate for the sample temp. Many online calculators available... I'm too lazy to search and link.

That's what I figured, but wasn't sure based on the way Palmer discussed it. There was no direct mention of compensating for temp and I wanted to be positive.

Compensating for temperature is a necessary step when using the hydrometer for any reading, I imagine he thought it was unnecessary to mention.

Check out Appendix A labeled "Using Hydrometers." There he discusses the need to compensate the temperature and lists a table of the necessary delta T's.

Hope this helps.

I don't know about anyone else i would be a little worried about dropping my hydrometer in 150deg wort. I usualy cool my wort before taking a reading, at least closer to 70. I guess that I would just worry about the hydrometer cracking or something from the sudden temp change.

Cheers

I believe they are also less accurate the farther from the calibration temperature you get (though don't quote me on that). That said I always cool to about 70F as well, though I rarely take a reading at the end of sparging anymore.