Great question! I don’t use the aerator that comes with it (which is needed for wine making), so that leaves a 1-2″ opening in the lid. I cover the container with a cloth then place the lid on top and clip it on, so the container is “breathing” but bugs and debris stay out. Hope that helps. 🙂

I noticed the 4 gallon fermenter comes with a lid. Do you use that lid when kombucha is brewing, cover with cloth instead, or leave the top open?

Absolutely! Great question! Go too SoulyRested.com/kombucha and print out the free printable there. It tells you your ingredients you will need for everything from a quart jar to a 4-gallon vessel. I highly recommend getting some rooibos tea for your first ferment to help you avoid any “vinegary” taste in your kombucha (CLICK HERE FOR A LINK TO THE ROOIBOS I LOVE.) or try this recipe. (CLICK RIGHT HERE) It’s perfect every time I’ve made it. (I’m assuming if you’re not crazy about the sourness of kefir you may not appreciate it if you kombucha goes a little vinegary.) Keep me posted and let me know how it goes!