This is part of my series on how I get things done. I hope it helps!

This is a continuation of my my simple coir substrate prep.

This procedure is exactly the same for pasteurizing casing material as well

I'll be taking the substrate jars and bags I loaded and pasteurizing them on the stove in a pasteurization bath.

I do this in jars or bags because I don't like letting my substrate sit and drain for hours after it comes into direct contact with the pasteurization water.

I also find it to be a relatively easy and mess-free ordeal.


Pasteurizing the substrate in jars

Quote:

This is not an exact science. You will need to tweak the timings and temps to your stove and situation.  I will describe how I do it every time with success.

---

I use 80-90 degree water for hydrating my substrate. No specific measurements, just make sure it feels cool or "room temp."

I mix my substrate very well and make sure it is evenly hydrated.

I load my substrate into jars as described here, making sure each one has roughly the same amount of substrate as the others.

To start, place a canning rack on the bottom of the kettle.



My kettle can hold seven quart jars but for this load I am doing six.



Fill with water, 1/3 to 1/2 of the way up the jars. No need to fill until they bob around and no need to use a brick to weigh them down.

In the past I would be concerned with submerging the jars as much as possible, but they will hold temp evenly when just 1/3 of the jar is submerged.



You can use a normal meat thermometer for this but I really like these $15 digital thermometers. This one has a timer as well as an alert that sounds when the substrate hits a certain temperature. Keeps me from having to look over it constantly.



I insert it into the middle of one of the jars in the kettle. This will measure the internal temp of the substrate.



I turn my stove on medium heat.



I place the lid of the kettle loosely on top, without turning it or putting the wingnuts in place. By putting the lid on at the start of the cycle, the jars will heat more evenly.

Quote:

It is important to know how many degrees the core temperature of your substrate will climb before the heat needs to be turned off on the stove.

---

Quote:

This will need to be adjusted based on the starting temp of the substrate as well as your stove and what-not. But the starting temp and timings laid out here work for me 99% of the time.

---

These will continue to climb in temp. Once they hit 140F, start a timer for 60 minutes.



With my timings, the substrate will continue to climb until peaking out around 160F just before the timer goes off. This is perfect.

If your temperature stops climbing or doesn't reach the high end of temps, just turn the heat back on to medium for another 5-10 minutes. It should get it climbing again without going over.

If the temp goes over 170F for more than ten or fifteen minutes, you will start to partially sterilize your substrate. It'd be best to toss it and try again. Since we spawn to bulk in open air, a partially sterilized substrate is often as shitty as an unpasteurized substrate.

Bear in mind though, if you are pasteurizing just coir and verm, you can probably get away with it. Coir is very contam resistant.

After the timer goes off, I remove the jars and put them in a tote or other container to cool overnight.


Pasteurizing the substrate in a bag

Lately I've been working on efficiency and pasteurizing the substrate in one big container is a great time saver.

I use large filter patch bags for this process.

One advantage of using filter patch bags is that you will have filtered air exchange during the cooling of the substrate. This isn't really a big deal for coir/verm but with substrates like hpoo or additives like coffee grounds, it never hurts to be as safe as possible.

One disadvantage of pasteurizing in bags is that is takes an extra hour or so to get up to temp.

I take my filter bag and fill it with substrate. Compress the substrate a bit so it stays in shape when moved around, try to get all the pockets of air out.



I twist the top of the bag and use a zip tie or twist-tie to the close it. I put the bag in my kettle (make sure to use a canning rack underneath) and I place a thermometer through the bag into the center of the substrate.



Fill the water about halfway up the bag. No need to add more water than that, no need to weigh it down. With the lid on during the whole process, the substrate will heat very evenly.



I turn my stove on medium heat.



I place the lid of the kettle loosely on top, without turning it or putting the wingnuts in place. By putting the lid on at the start of the cycle, the substrate will heat more evenly.

Quote:

It is important to know how many degrees the core temperature of your substrate will climb before the heat needs to be turned off on the stove.

---

First, take note of the starting core temperature. My bags usually start at 80-84F.

I let the core temperature climb 6-8 degrees F, then I turn the stove off.

Quote:

This will need to be adjusted based on the starting temp of the substrate as well as your stove and what-not. But the starting temp and timings laid out here work for me 99% of the time.

---

This will continue to climb in temp. Once the substrate hits 140F, start a timer for 60 minutes.



With my timings, the substrate will continue to climb until peaking out around 160F just before the timer goes off. This is perfect.

If your temperature stops climbing or doesn't reach the high end of temps, just turn the heat back on to medium for another 5-10 minutes. It should get it climbing again without going over.

If the temp goes over 165-170 for more than a few minutes, you will sterilize part of the substrate. It'd be best to toss it and try again. Since we spawn to bulk in open air, a partially sterilized substrate is often as shitty as an unpasteurized substrate.

After the timer goes off, I remove the bag and put it in a tote or other container to cool overnight.



I took some temps from around the top of the substrate to show that the temps are indeed very even throughout.





Ready to spawn? Here's how I spawn to a monotub

TranscendingLife said:

Once I turn off the burner on my stove, I put the lid on my AA, but don't tighten the wing nuts or put the toggle weight on.
Temps never exceeded 165F & it was complete set & forget, once temps were where they should be.

---

Thank ye, kind sir.

I'm going to give that a shot. I usually end up having to re-heat it a bit towards the end

YungSupreme said:

nice

---

Thanks!

Blake_Shroom said:

exactly how i do it. Not as easy as the bucket tek, but proper pasteurization is worth it.

---

FooMan said:

---

Thanks Foo!

BargainBab said:

Glad I'm not the only one who pasteurizes in jars.

---

I'm glad to see I'm not the only one who pasteurizes in jars either

NineInchNails said:

Great writeup!

This works great with ziplok bags too! You just have to get most of the air out of each bag before pasteurizing. I monitor the temp of one of the bags through the ziplok seal and the seal is closed afterwards. Once pasteurization is complete, the bags create a vacuum inside once cool.

---

Interesting...sounds like more work than jars tho
What size bags do you use?

Blake_Shroom said:

exactly how i do it. Not as easy as the bucket tek, but proper pasteurization is worth it.

---

NineInchNails said:

Gallon size ziploks. Not a lot of work really. Bags are disposable so it's sometimes convenient to not have to wash the jars. You don't have to fiddle with the bags much to get most of the air out. The bags will expand if you don't. No jars, no foil, just bags.

I've used jars too and both do work.

---

Disposable is exactly why I starting using the jar method. I used to use trash bags... yuck. So much waste... plastic in the environment is incompatible. I can't make you do it, but I can ask. Please go back to jars. I mean, really? Washing jars is too much work for you?

NineInchNails said:

Gallon size ziploks. Not a lot of work really. Bags are disposable so it's sometimes convenient to not have to wash the jars. You don't have to fiddle with the bags much to get most of the air out. I leave a corner of the bag unsealed and as the bag is imersed into the water most of the air escapes. I just zip the corner shut. The bags will expand if you don't get most of the air out.

I've used jars too and both do work.

---

elkart said:

Hey Frank, my problem with jars is that I can only fit 7 quarts in my PC, just undercutting the amount of substrate I need. What chamber are you growing in?

---

I can only fit seven in as well but I have two AA921s to make up for it.
My monos hold 14 quarts of sub and 6-10 quarts of spawn, filling it right to the 4" mark.
If I need to make multiple substrates in one day, I just keep cycling them, 7 at a time in each PC.
You can also use large stockpots, like the one in NIN's pic.

Thanks a bunch for the feedback guys, I'm glad I can give back some to the community here, you guys have helped me out a lot