How to set up lids and filters for the liquid culture jar?

6 min readMar 4, 2021

Liquid culture jars are utilized to sterilize media in preparation to be inoculated with a live mycelium culture. The lids and filters are customized to feature a filter of a self-healing injection port and fresh air exchange for hassle-free injection and liquid cultures extraction.

Having such reusable jars enables you to make your liquid culture with less risk of contamination.

Explore how to make your liquid culture filter and lids for your jars.

Materials You Will Need

For this tutorial, you’ll need the following:

  • Syringe filter

First off, you will need your syringe filters. It should be 0.22μm (micrometer). We don’t recommend using 0.45μm. You can get these syringe filters on Amazon, typically available in pink colors.

  • Self-healing injector ports

When it comes to gasket — the self-healing injector port — don’t try to get the grey ones, as they get chewed up so fast. We suggest getting the red ones. Ensure you buy the heavy-duty self-healing injector ports. The red ones last longer. Always get the nicer lids, especially if you are worried about the final product. Don’t compromise spending cheap on culture lids.

A multi-use self-healing injector ports make inoculation a breeze when creating your spawn. These materials are made from a special combination of high temp silicone and EPDM foam rubber along with a high temp 3M adhesive backing, which will stick and hold up to autoclave temperatures.

  • Metal lids

The liquid jar lid we will be using here is metal. You may be thinking, why metal?

Easy to clean. One reason is that metal is easy and stress-free to clean. There is a fact that metal is more challenging to work with than plastic lids. Nonetheless, most people don’t know that plastic lids do not typically seal to the jars. The good thing about metal lids is that they are made for canning. They already have a high-temperature seal built into them.

Some individuals are using RTV silicone and simply do it inside the white lid. That’s a reasonable thing to do, but with a metal lid, you don’t need to do all of that, as it’s already pre-made.

They are cheap. Another reason why it’s advantageous to use metal for your culture lids is that they are cheap. You can get them everywhere — from ball jars, cur jars, and more. Many jar manufacturers today have those metal lids.

It’s easier to work with. What’s more, we also find metal lids are simpler to work with than plastic, along with the drill press. However, you will find some drawbacks too. If you are working with a drill press, the metal lid is quite annoying.

They will catch many times and become little spinning blades that make it extremely dangerous to your hands. That’s why plastic lids are a much better option, especially if you are working with a regular hand drill.

But if you want to get a drill press, these are available between $60 to $70. Indeed, it may be a bit costly these times, but the convenience and ease it can offer to you when working with a metal lid.

One more thing. Considering we plan to use metal lids, you may be curious about rust. Rust is a common concern people have when using a metal lid. Just do take note that those rusts will be chewed up. Those eventually go bad. Good thing, a metal lid is disposable.

  • Forstner bit

When it comes to using your drill press, we will be using the Forstner bit. It punches right through your metal lid easily; no self-burrs, not to mention your self-injecting ports, will just pop right into the lid pretty easily.

You may need to fidget a bit, but it’s not that big. It enables you to make a smooth and the best seal. Forstner bits drill a flat-bottomed hole, making them a crucial tool for most hardware installations when an exact depth of mortise is needed.

  • Brad-point bit

This drill bit provides exact drilling in hard and softwood and can be utilized for through-holes and pocket holes. It’s a very sharp drill bit with a centering tip lets for precise hole positioning.

  • RTV silicone

Anyone making a liquid culture lid is familiar with an RTV silicone. It’s a silicone rubber that cures at room temperature.

  • Gloves

For your safety, always wear robust gloves or PPE.

How to Make a Culture Lid?

Now that you learned the importance of using metal lids and other things let’s start setting up our liquid culture lid. Without further ado, let’s dive in!

  • Punching the Lids

Sit down and take your stack of metal lids and go through on the drill press one at a time with your half-inch Forstner bit. Make sure you punch it right on the edge of the lid, just inside that lip.

Take all those punched lids, then turn them around the other way. Bring it slightly closer to the center, as your filter syringe has a wide disk on the top. Go down and punch right through again with the brad-point bit.

  • Putting the Pieces Together

For the next step, you are ready to put the pieces together.

Get your self-healing injector port and slide it on the big hole — the one you punched with a Forstner bit.

Grab your syringe filter. As you can see, there’s a smooth side and a lure lock. The former will be the one going in the lid you punched with a brad point bit. Put it through the top.

Get your RV silicone and run it right on around the ring. All you need is just a small bead. Let it cure overnight, and the following day, you’re good to go.

One tip when making your liquid culture lid: always pay attention to the lids. It’s extremely simple to pump those things out. But of course, if you don’t have a drill press, it will be a bit more challenging and complicated.

You can also utilize punches. We have noticed various individuals using metal punches too. But before we conclude, there’s one thing you need to keep in mind. Place the self-healing injector port first. Then put in your syringe filter. It is much complicated to put in the former, especially if you are trying to knock around the silicone syringe filter.

Hence, that is something you need to take note of.

For a final tip: always don’t skip on the parts you use on making your culture lids. Even if you buy those lids offered online, that would be alright. But if you will create your lid, do not ever skimp on the parts.

Ensure that if you will create them, create them well. At the end of the day, your lid will be going to be the most crucial thing. That’s especially true if you are working without a HEPA filter.

Are you planning to make your culture lid in your kitchen area? Well, you don’t want to have a skimped lid. You don’t want to have something that you didn’t put your best effort into. After all, who cares if it cost you a few more dollars if you are getting forty or more syringes. Does that make sense?

Consider how much important a culture lid is for you. Always bear that in mind in any decision you make in this business. Remember the end product as well as the end value extraction. Those two are what you like to concentrate on until you level up.

The best part here is that there are endless opportunities for you once you level up, such as lowering your costs. But you don’t need to force it, okay? It is still important that you make the most of your value extraction, even if you are only a home grower. Maximize the value extraction first, then work your way back into saving money wherever possible.

There you have it! These are the information you need to know when creating a liquid culture lid. You see, it doesn’t need to be that complicated and challenging. We hope you find this guide useful, helpful, and informative at the same time.

Are you now ready to make and set up your liquid culture lid? Just follow the tips and instructions mentioned in this guide, and you can make one in just no time!

What are your thoughts about this post? Share your insights with us by leaving your comments below! We’d love to hear more about them! Thank you for reading!

By Paul S.

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