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Agar & Light Malt Extract Powder (MEA)
Agar & Light Malt Extract Powder (MEA) FAQ
What is Agar & Light Malt Extract Powder?
Agar & Light Malt Extract Powder is a pre-measured dry mixture for preparing Malt Extract Agar, commonly called MEA.
The Light Malt Extract supplies nutrients for mushroom mycelium, while the agar turns the mixture into a firm gel.
MEA can be used for:
Testing liquid cultures
Mushroom tissue cloning
Agar-to-agar transfers
Culture isolation
Spore germination
Mycelium expansion
Preparing clean cultures for grain inoculation
How many agar plates does one packet make?
One packet makes approximately 500 ml of MEA, which is enough for around 20 standard 90 mm agar plates.
The exact number will depend on how much agar is poured into each plate.
Approximately 20 to 25 ml per 90 mm plate provides a practical starting point.
What is included in the premix?
The packet contains pre-measured:
Agar powder
Light Malt Extract
You only need to add water before dissolving and pressure sterilising the mixture.
Petri dishes, water, food colouring, media bottles and laboratory equipment are not included.
How much water should I add?
Add the complete packet to approximately 500 ml of distilled or purified water.
Using substantially more water may produce soft agar that does not set properly.
Using too little water may create an excessively firm or concentrated medium.
How do I prepare the MEA?
A basic preparation method is:
Add the complete packet to 500 ml of distilled or purified water.
Mix thoroughly in a heat-resistant media bottle or suitable container.
Warm the mixture gently until the powder has dissolved.
Leave sufficient empty space inside the bottle to prevent boiling over.
Loosen the bottle cap before pressure sterilisation. Never pressure sterilise a completely sealed container.
Sterilise at approximately 121°C or 15 PSI for around 15 to 20 minutes.
Allow the bottle to cool to approximately 47°C to 50°C.
Pour approximately 20 to 25 ml into each sterile 90 mm Petri dish.
Replace the lids immediately.
Allow the agar to cool and set completely.
Seal and store the finished plates appropriately.
Always follow the safety instructions supplied with your pressure cooker or autoclave.
Does the powder need to be sterilised?
Yes. The prepared MEA must be pressure sterilised before it is poured or used for mushroom culture work.
Mixing the powder with boiled water alone does not reliably produce sterile culture media.
The finished agar is nutrient-rich and can support mould, bacteria and yeast as easily as it supports mushroom mycelium.
Can I sterilise it in a microwave?
A microwave may help dissolve the powder, but it should not be relied upon to sterilise the prepared media.
For dependable culture work, use a suitable pressure cooker or autoclave capable of reaching approximately 121°C.
Do I need to boil the mixture before pressure sterilising it?
Warm the mixture enough to dissolve the powder evenly.
It does not need to be heavily boiled for an extended period.
Excessive heating can darken the malt extract, reduce water content and contribute to softer or poorer-quality agar.
Can I add food colouring?
Yes. A small amount of suitable food colouring can be added before sterilisation.
Colouring can make pale mushroom mycelium easier to observe and may help contamination stand out against the agar.
Only a small amount is required. Excessive colouring can make the plates too dark to inspect clearly.
Food colouring is optional and is not included in the premix.
Can the mixture be used for no-pour agar?
Yes. The prepared MEA can be placed into suitable heat-resistant containers and sterilised directly inside them.
This is commonly called the no-pour method.
Only use containers that:
Are heat resistant
Can withstand pressure sterilisation
Allow suitable filtered gas exchange
Will not deform or release harmful materials
Can be closed without becoming dangerously airtight during sterilisation
What mushroom species can be grown on MEA?
MEA is a versatile general-purpose culture medium suitable for many mushroom species, including:
Oyster mushrooms
Lion’s Mane
Shiitake
Chestnut
Enoki
Maitake
Reishi
Turkey Tail
Wine Cap
Chicken of the Woods
Portobello
Cordyceps cultures
Other gourmet and specialty mushroom cultures
Growth speed and appearance will vary between species and individual cultures.
Can MEA be used to test liquid culture?
Yes. Testing liquid culture is one of the most useful applications for MEA plates.
Place only one or two small drops near the centre of a sterile plate.
Keep the plate sealed and observe the growth before using the liquid culture to inoculate a large grain or substrate bag.
Our 10-Pack of Pre-Poured LME Agar Plates provides a ready-to-use option for customers who do not want to prepare and pour their own plates.
Can MEA be used for mushroom cloning?
Yes. A small piece of clean internal mushroom tissue can be placed onto the prepared agar.
The transfer should be performed inside a still-air box or in front of a properly operated laminar-flow hood.
Use a sterile scalpel and open the plate only as much as necessary.
Why has my agar not set properly?
Soft or unset agar may be caused by:
Adding too much water
Incorrectly measuring a divided packet
Prolonged overheating
Excessive sterilisation time
Incomplete mixing
Adding acidic ingredients
Pouring before the agar was properly dissolved
Allow the plates to cool completely before deciding that the agar has failed to set.
Agar normally firms as it returns to room temperature.
Why are there lumps in the mixture?
Lumps can form when the dry powder is added too quickly or is not mixed thoroughly.
To reduce lumps:
Add the powder gradually.
Use warm water.
Stir or swirl thoroughly.
Heat gently until the agar has dissolved.
Avoid allowing dry powder to remain at the bottom of the bottle.
A small amount of malt sediment or slight cloudiness can be normal.
How can I reduce condensation?
To reduce condensation:
Allow the sterilised media to cool before pouring.
Pour at approximately 47°C to 50°C.
Avoid pouring the agar while it is extremely hot.
Allow the plates to set in a clean, stable environment.
Stack the plates while cooling.
Store and incubate prepared plates upside down.
Avoid sudden temperature changes.
Do not open sterile plates simply to wipe away condensation.
How should the dry powder be stored?
Store the unopened powder:
In a cool, dry location
Away from direct sunlight
Away from moisture
Inside its sealed packaging
Away from strong odours and chemicals
Humidity can cause the powder to clump and may affect its performance.
How should prepared plates be stored?
Once cooled and sealed, prepared plates can be stored refrigerated at approximately 2°C to 8°C.
Keep them:
Sealed
Inverted
Protected from direct light
Inside clean protective packaging
Away from freezing temperatures
Away from raw food and spills
Allow refrigerated plates to return to room temperature while still sealed before opening them.
How long do prepared MEA plates last?
Prepared plates are best used while fresh.
Their usable storage period depends on:
Refrigeration
Plate sealing
Moisture loss
Cleanliness during pouring
Temperature stability
Agar depth
Do not use plates showing visible mould, bacterial colonies, severe drying, cracking or unexplained discolouration.
Is this premix sterile before preparation?
The dry ingredients are clean and pre-measured, but the finished media should not be considered sterile until it has been properly pressure sterilised.
Always sterilise the complete mixture before pouring plates or using it for culture work.
Is the MEA premix suitable for beginners?
Yes. The premix simplifies agar preparation by removing the need to weigh Light Malt Extract and agar separately.
The grower will still need:
Distilled or purified water
A heat-resistant media bottle
A pressure cooker or autoclave
Sterile Petri dishes or no-pour containers
A still-air box or laminar-flow hood
Suitable sealing film
Clean working techniques
Customers who do not have sterilisation equipment may prefer our pre-poured sterile LME agar plates.
Where is the MEA premix prepared and shipped from?
Our Agar & Light Malt Extract Powder is measured, mixed and packaged in Ireland.
Each packet makes approximately 500 ml of MEA, enough for around 20 standard 90 mm agar plates.
Fast shipping is available to customers across Ireland, the UK, Europe, the United States and Canada.
