These are so much easier to use. In conjunction with the 5 grain jars, No intrusions of contamination. Keep your needle hot, use with u/v light alcohol wipes and your favorite inoculation method, And rest easier knowing your jars are safe.

Best option imo to easily turn wide mouths into grain spawn jars. Excellent product and an excellent company

I was using un modded tek on my jars had to get rid of the metal lid tops because I had a lot of jars that would yeast out or contaminate having these provide me with more air flow an more protection I’ve seen a clear faster colonization rate in my jars and less contam definitely will be grabbing some more soon

I use these with 100% success to grow my mushroom cultures. I even reuse them and they never fail. This is a quality product and worth every penny.

These discs are great! What I did was punch three holes in the mason jar lid with a Philips screw driver. One hole directly in the center where I could inoculate with a spore syringe (the self healing port with these filters is directly in the center so you know where to punch the hole- punch it right where the "dimple" is in the lid) and two hole on each side of the center hole, about an inch away, to allow gas exchange for the growing mycelium. Well it has been 8 days at 83 degrees F and the sterile rye grain is colonizing very nicely. What is cool (I will try this soon) is that if you use Midwest's liquid culture kit with the 60cc syringe (find in "supplies."), you do not have to open any jars, essentially ensuring 100% success. Inject 5cc of spore syringe into the liquid culture... let mycelium form for 10-14 days or so... then use the 60cc syringe to suck up "liquid mycelium" and inject into jars of sterile rye grain using the method I mentioned above, flaming the needle between jars. Only 5cc of liquid mycelium per jar of grain will allow you to inoculate 12 jars. Not having to open any jars is the key as most contamination occurs at that point!

Thanks again for some awesome products Midwest.