What’s the difference between Spores and Liquid Culture?

Lots of beginners call every mushroom culture “spores” but there is a difference and it’s helpful to know the difference.

I usually say that spores are to mushrooms as seeds are to plants. It’s not entirely true but I think it’s an easy example. Unlike plant seeds, spores require 2 of them to meet in order to germinate and create mycelium. The fruiting bodies we like to eat form from the mycelium.

Liquid culture is created by taking the mycelium from the germinated spores and placing it into a nutrient broth. So liquid culture is more akin to taking a clone from a plant versus planting a new seed.

Both spores and liquid cultures often come in syringes because it makes it easy to store and inoculate with them. 

Spore Syringe

Spore syringes (also called an MSS or multi-spore syringe) are created by taking a spore print from a mushroom cap then putting those spores into a syringe with sterile water. 

The great thing about using spores is the genetic diversity. A spore syringe could have millions of spores. Every time 2 spores meet you’ll get different phenotypes. This allows you to selectively choose your desired phenotype. It’s really fun but it’s more of an intermediate skill level for mushrooms and I don’t suggest attempting it without at least a still air box. 

The downside of using spores is that they are much more difficult to capture cleanly. Probably the mushroom was exposed to open air during the cultivation process. This means that the spores captured likely have some amount of mold and or bacteria mixed in. This is why it’s highly recommended to put spores on an agar plate first. 

Agar allows you to test the spore syringe to make sure it’s clean and if it isn’t then you can “clean up” the spores by transferring clean mycelium away from any mold or bacteria.

There’s also a neat trick called “cabin sequestering” that helps separate clean mycelium from bacteria/mold by placing it under a little agar roof.

Liquid Culture

So liquid culture consists of mycelium in a nutrient broth. Mycelium is created by germinating 2 spores. I usually create mine by placing a small cut of clean mycelium from an agar plate into a jar of nutrient broth. My broth is made by adding .5g light malt extract per 250ml of water and sterilizing in a pressure canner for 30 minutes at 15psi.

There’s a couple main reasons to use liquid culture instead of spores. 

1. It colonizes faster. Spores take several days to a week to germinate. Liquid culture is already germinated.

2. It’s much, much easier to create cleanly compared to spores. It’s still a good idea to test your liquid culture on agar if possible but I usually assume that liquid cultures are clean and spores are dirty. Injecting spores directly into a growing medium without testing on agar is a high risk for contamination, even from a reputable vendor.

3. Liquid culture can be quickly expanded. A single syringe of liquid culture can inoculate 10 jars of liquid culture and in just a couple weeks become 250 syringes. You could then do it again and turn 250 syringes into 62,500 syringes. If you did it once more that would be over 15 million syringes. 

If you don’t have access to agar then you should definitely use liquid culture. Some vendors for the manure loving mushrooms will call liquid cultures “isolated spore syringes” because liquid culture for the manure loving mushroom variety exists in a bit of a gray area legally. 

Note: I should make a disclaimer that anything I say related to “manure loving” mushrooms is about microscopy purposes only and not related to cultivation, because that would be illegal.