The following grains have been mixed together:
Can I mash these together @ 150°F for about 45 minutes then increase the temperature up and let them steep at 165°F or so to gain a higher conversion in the specialty grains?
This will then be brewed with X lbs. of extract.
Topic mashing temperature homebrew
Category Mac
You will get full conversion at 150°F. If it will within 45 minutes depends on a lot of other conditions. Mainly pH and water grist ratio. Just do an iodine test to know when it actually done. More time and even a very troubled mash will stil complete.
Increasing to 165°F will denature your enzymes and saccrafication will stop.
"Specialty Grains" usually refers to roasted or Carmel grains. Which have already had thier starches converted in the malting process. Raising to 165 for thier sake will do nothing of benifiet. Their sugars will extract just fine at 150. This is reference to your carapils and Crystal malts.
What you are referring is called multi step mashing or multi rest mashing.
There are many good article about this :
But to answer your question, yes you can do it. Should you? Take a look at #3 for more information.
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