Liquid Cultures vs Agar Dishes

Liquid cultures vs agar dishes! Let’s talk about the differences between the two. Is one better than the other? Keep reading and we will certainly give you our opinion on which is the best option.

Liquid Cultures

Liquid cultures certainly seem to be more popular than cultures on dishes. This is most likely due to their ease of use. Liquid cultures psychologically give the cultivator a sense of security for those who have doubts about their technique.

liquid culture in front of laminar flow hood

Preparing liquid cultures can be done in multiple ways. A popular method is by introducing spores to a nutrient-rich broth that has been sterilized. The spores germinate in water and produce mycelium. The mycelium can be broken up by using magnetic stir bars that keep the broth moving so the mycelium stays fragmented. This makes it easy to load into syringes.

Multispore vs Isolated Strains

Realistically, this method should be considered a multispore inoculation. The culture isn’t an isolated strain. This will produce varying results because the liquid culture will possess different genetics. This makes it nearly impossible to project what your end results will be when it comes time to harvest your mushrooms.

The preferred method for preparing liquid cultures is with an isolated strain. We grow the mycelium out on an agar dish. When full colonization is reached we blend the culture in sterile water. After blending the liquid can be loaded into syringes or expanded into a nutrient-rich broth as we mentioned above. This is also known as a liquid inoculant.

Unforeseen Issues

A major problem with liquid cultures is if it is contaminated you most likely will not know until you have transferred it. This makes for all sorts of trouble when contacting your vendor. It becomes too difficult to prove who was at fault, they may give you a lot of grief about a replacement or refund.

Liquid cultures are excellent for beginners who are still trying to nail down a good clean technique. Before buying a liquid culture from anyone always contact the vendor and ask how the cultures are prepared. Spores germinated in a nutrient-rich broth are highly overrated. The results will vary due to the mass collection of genetic strains held by a tiny 10 ml syringe. You want a liquid culture prepared from an isolated strain. You will thank me later.

Agar Dishes

In my opinion, this is where the rubber meets the road. Sure, you’ve been cultivating for a long time with liquid cultures. It is time for you to start your journey in preparing agar dishes.

mycelium growing on an agar dish

If your skill set is a combination of the two methods, that’s fantastic. Solely, working in liquid cultures is somewhat an undesired practice. Don’t get me wrong. Some species thrive from a liquid culture inoculation.

Preparing cultures with agar dishes will help you out so much in the long run. They will boost your confidence in your sterile technique. You will get to know the behaviors and mycelial characteristics of different species of mushrooms.

Don’t be scared!

Some of the best mycologists today were once terrified of pouring their own agar dishes. It can be nerve-wracking to think about, especially if you have experienced anxiety in the past. Yes, they can be easily contaminated. This is what makes future mycologists of Earth want to shy away.

When people have projects that contaminate they see it as a failure. Having agar dishes contaminated is an excellent time to work on your technique. The room you working in could use a good scrub down, maybe it’s time to ditch the SAB and get a flow hood.

It’s important to always remember that the biggest contaminant in any lab is YOU. Human beings in a laboratory are walking contamination sources. We have fungal spores on our clothes and skin and we are crawling with bacteria. Always make sure that you are clean before labwork.

Liquid Cultures vs Agar Dishes

I’m telling you this because I want to encourage you to switch to working with agar. You can always prepare your own LC. As we mentioned earlier you won’t always see the contamination in an LC until it’s too late. But it is easy to spot them in a petri dish culture. A contaminated culture in a petri dish isn’t the end. You can transfer clean tissue from a contaminated dish to a fresh agar dish. This is called cleaning a culture.

When you have cultures in agar dishes you can create slants to preserve your strain. You can use one dish to make several other dishes to use for multiple projects. Cut wedges and transfer to grain to begin making grain spawn. You can transfer wedges to sterile water and blend them into a solution to prepare your own liquid culture.

The benefits of cultures on agar dishes outweigh the benefits of solely working with liquid cultures. That doesn’t include purchasing a liquid culture and inoculating agar dishes. As we mentioned earlier, finding a reputable vendor for liquid cultures is recommended. Preparing an LC is easy to mess up. Everybody likes to blame everybody else and it’s difficult to prove who did it.

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