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Additives & Chemicals
Light Malt Extract (LME)
A food-grade dry powder made from malted barley. It is the standard sugar base for malt extract agar and malt extract liquid culture, the two media most home growers use to grow and keep clean mycelium.
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100 g pack. Made for lab and cultivation use, not for eating raw.
Concentrated extract of malted barley, nothing added
One powder covers both your plates and your jars
Mixes into water on heating, keeps dry for a long time
The short version
Light Malt Extract is the dried extract of malted barley. It is the sugar-rich nutrient base in two of the most common growing media: malt extract agar for petri dishes, and malt extract liquid culture for jars. Add agar powder and you get plates. Leave the agar out and you get a clear broth for growing culture in liquid.
It is simple to use. You weigh it, dissolve it in water, sterilise in a pressure cooker, and let it cool fully before you work with it.
WHAT IT IS
What Light Malt Extract is
Light Malt Extract, usually shortened to LME, is the concentrated extract of malted barley, spray dried into a powder. It is the same product used in home brewing, where the dried form is also sold as dry malt extract. In the lab it gives mushroom mycelium an easy supply of sugars to feed on, mostly maltose, which is why it has long been a standard base for fungal culture media.
This is the light grade, which keeps the medium pale. A pale medium makes it easier to see your mycelium and to spot any contamination early.
HOW TO USE IT
Making malt extract agar (plates)
Agar plates let you grow culture on a surface so you can see it clearly, clean it up, and split it. A common working recipe is below. It scales up or down in the same proportions.
| Water | 250 ml |
|---|---|
| Light Malt Extract | 7.5 g |
| Agar powder | 5 g |
That works out to about 30 g of malt extract and 20 g of agar per litre, which is the usual lab strength. Use distilled or clean water.
Weigh and mix
Weigh the LME and the agar, then stir both into the water until the powder is wetted through.
Pressure sterilise
Pressure cook the loosely capped container at 15 PSI for 15 to 30 minutes. This melts the agar and kills bacteria and stray spores. Do not run it much longer, as the sugars can caramelise and darken the medium.
Cool then pour
Let it cool to about 45 to 50 C, still liquid but no longer scalding. Pour into petri dishes in front of a clean flow or in still air. Let them set, then store inverted.
HOW TO USE IT
Making liquid culture (jars)
Leave the agar out and you have a malt extract broth for growing culture in liquid, ready to draw up and inject. Keep the sugar level low. Most growers use roughly 4 to 10 g of LME per litre of water, around half a percent to one percent sugar. Too much sugar makes the broth cloudy and harder to keep clean.
Mix and fill jars
Dissolve the LME in your water and pour into jars fitted with a self-healing injection port and a filter or micropore patch. A stir bar dropped in now helps you mix later.
Pressure sterilise
Pressure cook at 15 PSI for 15 to 25 minutes. Let the cooker cool and depressurise on its own before opening.
Inoculate and grow
Once fully cool, inject your culture through the port using clean technique. Swirl now and then over the following days as the mycelium spreads.
STORAGE AND CARE
Storage and what it is not for
LME powder is sticky and will clump if it picks up moisture. Keep it sealed in an airtight tub, ideally with a desiccant pack, somewhere cool and dry. Made-up plates keep best sealed and inverted in the fridge at about 2 to 4 C. The fridge is the right place for set agar. Freezing can crack the gel and draw out water, so it is best avoided for working plates.
This is a nutrient base, not a sterilising or cleaning agent and not a substrate on its own. It always needs heat sterilising before use. On its own it grows nothing useful and will spoil if left damp and warm.
Common questions
Frequently asked
Yes, it is the same kind of dried malted barley extract. The light grade keeps your medium pale so contamination is easy to spot.
Yes. Add agar powder for plates, or leave it out for a liquid broth. The malt extract is the food source in both.
Yes, always. Pressure cook any made-up medium at 15 PSI before use, 15 to 30 minutes for agar and 15 to 25 minutes for liquid culture.
Plenty for a home lab. At around 5 g per litre for liquid culture that is roughly 20 litres of broth, or many batches of plates at agar strength.
Usually too much sugar or a sterility slip, not the malt itself. Keep liquid culture light, around half a percent to one percent sugar, and work clean.
Both feed mycelium the same way. The light grade gives a paler medium, which makes it easier to read growth and catch contamination, so it is the usual choice for lab work.
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Sold as a laboratory and cultivation nutrient base for legal gourmet mushroom cultivation and microscopy use. Sterilise before use.
We work hard to keep this information accurate and to cite reputable sources, but the occasional mistake can still slip through. Always check the product label and a current reference before relying on any figure for something important.