Liquid culture is a sterilized nutritious solution which can be used as a media to grow, store and use mycelium tissue while growing mushrooms.
By the end of this post you should know how to make liquid culture for growing mushrooms and have some photos of good/bad cultures to analyse.
The liquid culture recipe I am going to discuss in this post uses honey which isn't the greatest medium (because of the slight colouration) however it is probably the most accessible to everyone and definitely works.
This techniques discussed require you to have and use a pressure cooker, if you don't have one checkout my post about the best pressure cooker for growing mushrooms at home.
How To Make Honey Liquid Culture?
The recipe for a honey liquid culture generally consists of a 4% honey-to-water mixture. The mixture is sterilised and inoculated with mycelium.
Next, the jars are left to incubate at 80-85 (26-ish c) degrees for several days until a white mycelium clump will grow and the rest of the solution should remain transparent.
A basic outline of the steps are as follows:
- Mix 4% honey/water mixture.
- Sterilize the mixture in jar.
- Innoculate jars with mycelium.
- Wait for mycelium growth. Shaking the Jar regularly.
Step By Step Guide to create Liquid Culture
The following steps describe how to make a 400ml Jar of Honey Liquid Culture in full. We recommend creating multiple jars at one time to improve the chances of creating a clean Liquid Culture.
- Pressure Cooker
- Micro-pore tape/polyfill (here is a discussion on gas exchange lids, however for this tutorial micropore tape will do).
- Liquid Culture Syringe
- Butane Torch (seriously get one of these it makes flame sterilizing needles very very easy, the needle will glow red in seconds).
Step 1 Create Mixture
- Find a Glass jar and put a hole in the lid using a screwdriver or scissors
- Fill the Jar with 400ml of warm water (distilled water preferably).
- Add 4 tsp of honey to the water (Approximately 16ml).
- Stir the mixture until the honey dissolves into the water.
- Place micro-pore tape and foil over the lid covering the hole and screw on lid.
Step 2 Sterilize Jars
- Place the Jars into your pressure cooker and sterilize for 30-40mins at 15psi.
- Allow the pressure cooker to cool down for a few hours before moving to the next step.
Note: Some people say 15-30 mins because the sugars will caramelize any time longer; I’ve never had mycelium not take to 'caramelized culture', however when I use 15-30 mins I have had contamination.
Step 3 Inoculate Honey/Water mixture
- Remove jars from the pressure cooker.
- Wipe the lid of the jar with alcohol wipes.
- Shake needle to spread out current mycelium.
- Flame sterilize needle until it is glowing red.
- Insert syringe and inject 1cc of liquid culture.
- Remove the syringe and flip down the micropore tape.
- Place the jar into incubation temperatures(18-20c or 64-68f).
Step 4 Wait
- Stir the jar daily to prevent clumpy solid mycelium masses (without opening the jar).
How to use Liquid Culture?
- Sterilize a syringe by filling it, then emptying it with boiling water 3-4 times.
- Wipe the liquid culture jar lid with Alcohol Wipes.
- Flame sterilize the needle until glowing red then insert into hole in the lid of the jar.
- Pull back on the syringe until you have collected some mycelium.
- While removing the syringe, cover the hole with micropore tape just as the syringe leaves the jar (has to be fast).
Note: If the mycelium clumps are too big for the syringe then pump the syringe inside the jar a number of times to break up the mycelium into small pieces.
What does good/bad Liquid Culture look like?
The liquid should be clear and you should be able to see through to the other side of the jar. Inside the liquid, there should be a white clump of mycelium or lots of little clumps.
Common signs of contamination are if the culture is cloudy and you cannot see through it (wait a week after inoculation to check this as sometimes the mycelium cleans up the culture), if it releases a foul smell or has a green colour scum on the top of the culture when it is left to settle for a few days.
Normally the best way to find out if the culture is clean is to try it out on grain or agar and see if it contaminates. If you follow sterile technique but the jars are repeatedly being contaminated in the same way it’s likely your jar of liquid culture.
Why make Liquid Culture?
- Faster Growth – Since the medium already contains live mycelium it normally colonises a substrate substantially faster. This gives LC an advantage over spores.
- Unlimited Mycelium Supply – if you learn how to make liquid culture you can turn 1 LC syringe into an unlimited supply. However, you must take senescence into consideration (so use a master jar).
- It’s Cheap – making liquid cultures is very cheap and can be done with household ingredients.
Does making a Liquid Culture Require a Pressure Cooker?
Actually, no, you can sterilize the honey water liquid culture recipe in a microwave if you don’t have a pressure cooker. Place your mixture into a microwavable container, the put it inside the microwave for 3 minutes, remove and shake, then place it in for another 3 minutes.
How Long does Liquid Culture Last?
Liquid Culture can survive at room temperature for 6-12 months until the nutrients in the solution have been used up. So you're Liquid culture is good for a decent amount of time suspended in the solution.
If you need to your liquid culture to last longer putting it into a refrigerator should allow it to survive for years.
When to Stir/Shake Liquid Culture?
It is recommended to shake or stir (using a magnetic stirrer like this) at least once a day. If you don't do this the Mycelium will create a huge blobby mass as seen in the featured image of this page (at the top). This also speeds up the expanding process as there is more surface area for the Mycelium to grow off.
I did not shake those Jars so I could highlight what a clean culture would look like (clear).
How Long Does Liquid Culture Take?
Liquid culture usually takes between 7-14 days to accumulate enough mass to be used in an actual inoculation.
It can take longer for the Jar to be completely colonized and the growth to slow down.
Several factors can come into play here such as whether you shake the culture, temperature and Mycelium vigour.
Alternatives to Honey Liquid Culture?
Stick to the ratio of 4% sugar nutrient to water.
- Light Malt Extract.
- Corn Sugar.
Which is the Best Liquid Culture Recipe?
If you are looking at the list above and wondering which of these is credited with being the best liquid culture recipe you have to understand this is always going to be subjected and so many factors can come into play including cost and availability in your specific area.
The recipe with the reputation as best liquid culture (online) has to be the Light Malt Extract (LME), it colonizes fast and creates a thick mycelium and outperforms others on this list.
However, there is one last recipe/method which may interest you when it comes to making a mushroom liquid culture recipe. It is possible to use the Grain water from any Grains you are preparing as spawn to create liquid culture.
So if I was preparing Rye grain I would use the water which the grain was boiled in as a liquid culture nutrient. This has the added benefit of allowing your Mycelium to grow and consume the nutrient which it will be inoculated into, thus reducing the colonization time (as the Mycelium already has the digestive enzymes to breakdown the grain).
In my opinion, grain water Liquid Cultures like this are the best liquid culture recipes as the Mycelium had adapted to fit the next stage of growth.
Liquid Culture vs Agar?
I believe liquid culture is easier to work with for beginners with the only caveat being, if you are using a spore syringe (instead of liquid culture) then it is always recommended to inoculate agar first. However, this is a highly debated topic online.
When I was just beginning mycology I had a lot of success with liquid cultures so maybe I am a bit biased.
Taking my second 10cc LC syringe I’d bought online and expanding it into honey liquid culture jars at home was a very easy procedure.
Learning the technique described above resulted in me having an unlimited amount of spawn to work with, so making mistakes never became a financial problem.
Although these days I gravitate towards agar dishes since I created this cheap flow hood (not laminar but it works).
Is it possible to make Liquid Culture from agar?