I figured I would try and give good pictorial and explanatory way to pasteurize straw/poo. This method will work for any kind of ratio of your substrate. I like to use a ratio that is close to 60-70% straw and 30-40% poo. Straw is not recommended if using horse manure as it already contains anti-bacterial straw.
1) Get your straw and chop it up to pieces that are no bigger than 3 inches (I like to keep most of mine at about 1" length).
2) Shred your poo so there are no chunks. Mix in your poo whatever kind you choose to use. Make sure that if you have gotten it from a cow field or horse stable that it has been properly leached and dried.
3) Mix straw and poo together and place into a pillow case. Then tie the pillow case in a knot (this would be a good time to place in your meat thermometer or whatever kind of thermometer you decide to use) Do not use a candy thermometor as they will break.
4) I use a roaster oven I think it is called to place my straw/poo into to pasteurize, but you could do this in a pot on the oven or in the stove.
5) Submerge the pillowcase with hot water. Using hot water will take down some of the time that you will have to pasteurize, because it doesn't have to heat as much. You will probably have to put something on top to weight it down to stop it from floating.
*Optional* I like to let my straw/poo soak in the water for about an hour before pasteurizing.
6) Now you're ready to start pasteurizing. Put into the oven or on the stove or in the roaster. If you're using a roaster like the one pictured you can set the temp to 170 and walk away for a couple of hours (I have found that the temps on mine are very accurate). It would still be a good idea to use some kind of themometor in the bag so you could see the temp. If using a stove you need to sit with it for a bit till it gets to 170 and make sure not to let it go over 180 which will be in the gray area of in between pasteurization and sterilization. Use a meat thermometer to stick down in the bag with the top sticking out to make sure you do not exceed these temps. (I like to pasteurize for 2 hours (after temps get up to 170), but some people say that you don't need to do it that long so it is up to you on that part.
7) When your time is up, take your pillowcase out of the water and place it in the sink over a rack so it can drain and cool over night.
8) After the substrate has been properly cooled, I squeeze the bag well to get the excess water out. When you squeeze a handful of substrate there should be barely any water drops dripping out of it.
9) Now you're all pasteurized and ready for that bulk grow! Have Fun
This is straw/poo, pasteurized by the method above, layered with colonized WBS after 3 days of incubation. by pinkfloydms