We have all seen the the different recipes revolving spent grains, from dog treats, breads, and pretzels. There is no really simple way to do it and it becomes a mess stinky PITA if you are not lucky or move fast. Well that is all over!
I have been using the following technique with 100% success and is so simple anyone can do it. It not only allows the harvesting of spent grains but it also produces wort that I have been using for starters reducing the need for DME by a remarkable amount.
1st after you have collected the last of your wort for the beer you are brewing and it is being heated to a boil, I add in 2-3 trays of ice cubes (basically free) and filtered water or drinking water that is hose temp or 70F-ish (cooler is also fine) to the MLT. I try to get it right about the same 1.25-1.33 volume the same as any mash. I mix it up and then put the lid on the MLT and allow it to sit for 30-40 minutes. I vorlauf as normal and then collect as much of my "cold mash" as possible.
The cold mash will force the grain temps to drop past the point where the natural bacteria cause that "bad grain smell and taste" to go bad. I then boil this wort for 15 minutes on the stove or a separate burner if I have one open, check the gravity to get an approximate OG. I will then allow this wort to cool, normally in a water bath in the sink and decant the wort off the break + protein material in the bottom of the kettle, into Pint and/or Quart Mason Jars.
These jars will get pressure cooked for 20 minutes with a 15 pound weight. This is necessary if storing the wort at room temps. If you do not have a large pressure canner you can use a standard canner and boiling water bath to help sterilize and seal the jars. Wort starters made this way should be kept in your fridge.
NOw we have cool grains which are so much easier to work with. I set my oven to the lowest temp (mine is 170F) and turn the light on inside the oven. I spread some of the grains out on a cookie sheet (I got a set of super cheap ones for a few dollars) and put them in the oven. I try to make the grains even with the side of the cookie sheet and my oven can hold 2 large and 2 small cookie sheets for drying. I fluff the grains by hand and reset them so they are not piled up in the middle about every 4 hours. Normally this takes overnight to get the grains good and dry and I do NOT get up to fluff them.
When they are dry, I bag them into gallon Ziploc bags and store them that way marking what the beer was on the outside. A stouts grain bill makes a great dark bread while a pilsner is good for crackers/pretzels.
You can crush the grains into powder and use them as a flour substitute (note: that it does not have much sugar so I sub out 50% or less of what a recipe calls for in flour.) Or use the grains as are to add more texture to breads and crackers.
PS: If you do not want to dry the grains you can still compost them or do what you normally would do with them. They should not smell nearly as bad, as quickly as they do when not cooling them.