7 Best Liquid Culture Recipe (Oyster, Light Malt Extract, Dextrose, Karo, Cordyceps, Grain Water)

You might feel more like a scientist, mycologist, or hobbyist if you use liquid mushroom culture to grow mushrooms.

It’s not necessary to have a degree in order to make your own mushroom liquid culture or grow mycelium for your garden.

What is Liquid Culture Mushroom?

Liquid culture is a sterile mixture made up of water and one or a few sugars. We will provide the liquid culture recipe in the following. Once the mixture has been inoculated, it is intended to stimulate mycelium growth.

Liquid culture could be described as floating mycelium in a nutrient-rich broth. Inoculating substrates is easier with liquid culture. After the mycelium has grown in the sugary, nutritious broth, you can inoculate the mixture onto any substrate or store it as living mushroom cultivation.

Oyster Mushroom Liquid Culture Recipe

It is both time-savings and rewarding to maintain your own mushroom culture library. Although it takes time to master, there are many methods you can use with minimal equipment. A pressure cooker is the most important piece of equipment you will need.

Oyster Mushroom Liquid Culture Recipe
Oyster Mushroom Liquid Culture Recipe

Two types of mediums are used to store cultures. Liquid cultures are often criticized in the mushroom community because it is harder to identify when they have contamination. You can still ensure that your liquid cultures are free from contamination by following a few simple steps, even if you don’t work in a sterile area.

What you really need:

  • Zavor Pressure Cooker 15 PSI (Recommended)

  • Jars with an airport lid
  • Syringe and needle, preferably 16+ gauge
  • Alcohol spray or alcohol wipes
  • lighter
  • Gloves

It is easiest to make your own liquid cultures by using a culture obtained from a trusted supplier. Then, you can expand it to become a more liquid culture. These are the steps:

You can add liquid culture recipes to your airport containers. These typically contain tap water and some sugar/nutrients

To sterilize the liquid culture, pressure cook the airport jars

To sterilize liquid cultures, add a little master culture

Wait for the culture to grow before you use it to inoculate your grain spawn or fruiting substrate.

Liquid culture added to airport jars

This step is easy. The only thing that requires some trial and error is figuring out the best recipe for the particular mushroom you are trying to grow. Tap water and maple syrup are the best options for oyster mushrooms and shiitake. Add 1 teaspoon of maple syrup to 1 cup of hot water. Mix it well and then add to the jars with airport lids. My liquid culture jars are filled to the top leaving approximately 5cm (2in) of air. This makes it easier to extract liquid with a syringe and allows for some evaporation.

To break down the mycelium, it’s a good idea also to add something to your containers. A professional uses a stir-bar and puts their culture on a magnetic stir plate. However, you can also add marbles or broken glass into the jar. This will allow you to break down large clumps and prevent your culture from becoming clogged when you inject it into a needle.

Before pressure cooking, it’s a good idea for aluminum foil to be placed on top of the jars. This protects the filter from becoming too wet, and it also keeps the jars from being exposed to contaminants until you are ready to remove the foil.

The liquid culture can be pressure-cooked

For approximately 15-20 minutes, add the jars and pressure cooker to them. Follow the instructions and never forget to add water above the base plate. Allow the culture to cool down to room temperature. This will likely take several hours and I often let it cool overnight.

You can also add mother culture to your liquid culture

After letting your jars cool down, prepare your master culture, alcohol wipes, and lighter. To break down the mycelium, shake your master culture vigorously. The needle will be sterilized if it is your first time using the syringe. Remove the top of the first jar. Push the needle through the self-sealing injection port. Add 1-2 ml liquid culture to the jar. This process can be repeated with all pressure-cooked jars.

It’s a good idea if you don’t use alfoil to clean the injection port, to wipe it with an alcohol swab before inserting a needle. You can spray it with your alcohol spray (70% alcohol/methylated spirits, 30 percent water).

You will need to sterilize your needle before you reuse it. Connect the needle to your syringe, and then move the needle back and forth over the flame until it is hot. To cool the needle, you can either squirt some culture or wipe it with an alcohol wipe.

Place it on the shelf, and let it grow.

Most mushrooms thrive at temperatures around 25C. Outside of that, they will grow slower. My jars are kept indoors for the first 4-7 days so that the mycelium can begin to grow. As it begins to consume the sugar, you should begin to see mycelium grow slowly. To introduce oxygen to the liquid and break down the mycelium, stir the culture once a week.

Once the mycelium has taken up too much volume in the jar, vigorously stir the liquid culture until it is broken down. Next, tilt the container so that the liquid culture is up against the injection port. Then, using a sterilized syringe with a needle, you can inject the liquid culture into your syringe until it is full. Now your syringe can be used to inject grain jars.

You can check my 9 Best Chicken Of The Woods Recipes if you are interested.

Light Malt Extract Liquid Culture Recipe

Let me start by saying that I am a giant on my shoulders. I’m not trying to reinvent the wheel. I have combined various sources to create a Tek that suits my needs.

Light Malt Extract Liquid Culture Recipe
Light Malt Extract Liquid Culture Recipe


  • Pint Mason Jar
  • Small Shard of Glass/Marbel/Coin
  • Hydrophobic Syringe filters
  • Heavy Duty Self Healing Injection Ports
  • Set of Electric Drills
  • Drill Bits (1/4” and 5/32″ respectively)
  • Light Malt Extract (Rye). – Visit your local brewery supply store
  • Measuring cups
  • Scale
  • H2O (Tap, Distilled, Reverse Osmosis, etc.)
  • Sharpie Marker and Label Maker
  • Rubber band or wristband
  • Aluminum Foil
  • RTV (optional, not necessary for success)
  • Pressure Cooker (duh.)


First, create your liquid culture lid. Use your 1/2″ bit to drill where the Ball logo is. The injection port should be located as close as possible to the jar’s wall to ensure that it does not hinder functionality.

Next, drill a hole of 5/32 inches for the syringe filters. This should be done opposite the place where you have added the injection port.

When drilling holes, be sure to consider the size of your syringe filter once it has been installed. Your injection port and the syringe filters are now complete.

They should fit together without any additional RTV. However, if necessary, you can add some.

There is much confusion about the optimal ratio of nutrients to water in liquid culture. Most people add sugars to water at a 4% dilution. This ratio results in opaque liquid culture for light malt extract (LME).

Clearness is the best quality for any LC tek. This is because it provides a neutral background that allows the grower to see the growth taking place.

Clear liquid cultures can become cloudy from yeast fermentation and bacterial contaminations. The clarity of our LCs is the first indicator of the batch’s quality.

You can also allow an LC to rest for a few days after it has been sterilized under pressure to check if it is clean. Inoculation can be done if the LC is still clear after several days.

These are the best ratios (IME) for light malt extract LCs:

  • 1g/600mL
  • 0.40.5g/250mL

Scale your LME and add it to your jar. Attention: LME can be very sensitive to water. It can clump due to the moisture on your skin. To help me weigh the things, I use a spoon. Then I pour water on the scale tray to rinse the LME out of the jar. Make sure your jars are completely cleaned before starting any liquid culture recipe.

After you have added all the ingredients, put the glass shard/marble in the jar. Shake the mixture till it becomes homogeneous, then cover it with an ordinary mason jar lid.

Place your custom LC lid tightly on the jar, cover it with aluminum foil and secure it with a rubber wristband. Finally, place it on your computer. Rubber wristbands are more durable than rubber ones because they can last for countless cycles.

How much water should I use?

You should add about 40% to grains, or approximately half an inch to the base of the container. (Note: I mean half an inch, which includes the extra jar rings as well as the traditional spacer that is placed at the bottom of your PC.

Here’s the trick to clear liquid cultures

For 25 minutes, pressure cook at 13psi for 25 minutes. This is what I mean by fluctuating between 14psi to 11psi with an overall average of 13psi. I prefer to heat to 14psi, then let the pressure drop before adding more heat. This should only be done a few times before the timer runs out.

This will keep you from burning sugars in the LME while also achieving sterilization pressures that are high enough. A constant 15psi will produce an opaque media, making contamination difficult to detect.

Please keep in mind that results may vary based on your location. These parameters provide a good starting point. You can adjust them as you wish.

After the time has expired, turn off the heat and let the LC cool in the pressure cooker for several hours. Failure to remove the LC from the pressure cooker soon can result in shattered glasses. The “top” gauge should be depressurized but the lid must remain on for at most two hours. This will save you money, time, and heartache.

After the LC has cooled, it can be inoculated using any species you choose.

Have a peek at my 8 Best Pumfu Recipe if you are interested.

Dextrose Liquid Culture Recipe

To inoculate your substrate, liquid (or tissue) cultures can be used to grow mycelium. Similar to a multi-spore culture, but the spores are already germinated and have formed a network. Because the spores have already germinated, colonization times are significantly faster. Inoculated substrates also have an advantage over contamination.

Dextrose Liquid Culture Recipe
Dextrose Liquid Culture Recipe

One spore syringe could be used to make gallons worth of liquid culture. One spore print, agar cultures, and mushroom tissue can yield gallons.

Liquid cultures can be economical as 1cc of a spore-syringe can provide you with large quantities of liquid inoculant that can be used to inoculate many jars/bags. If the liquid inoculant used is a clone, which can be generated from mushroom tissue or sectored agar, each jar should have similar maturity and growth rates.

Liquid cultures can be utilized with 4% sugar and other nutritional solution.

This means that for every 96 ml/cc of water, 4 grams of sugars are required. (A gram of water weighs 1 ml/cc.)


These are some of the sources of nutrients:


Sugar (also known as sugar in households) should not be used.

Although Dextrose is not recommended alone, it can be used. Its development may be slower due to the lack of additional nutrients, but because it is clearer, you may be able to notice contamination more easily.

Honey and light malt extract can be used together. You can add nutrients such as peptone or other flours, but it is difficult to determine the stage in mycelium growth because of cloudiness.

Weighing 1 tablespoon light malt extract and 1 teaspoon dextrose was done. These are the final weights.

  • 1 tablespoon light malt extract = 10.3g
  • 1 tablespoon dextrose = 10.1g

Take or leave a point of one gram.

Malt and Dextrose

1 tablespoon dried Malt Extract or Dextrose to 250ml (1 cup) water is used by one member.


  • 2% light-malt extract, 2% dextrose
  • This would be around 1/2 teaspoon dextrose, 1/2 teaspoon light malt extract per 250ml (1/4 cup) of water.
  • 1 teaspoon dextrose (or light malt extract) every 75 milliliters of water or 1 1/4 teaspoon dextrose or light malt extract per 100 milliliters of water

Honey from organic

  • The 4 percent ratio is represented as 4 cc/ml. You may measure the amount of liquid without using a needle by using a syringe.


Don’t be alarmed if your solution is between 3% and 5%. In most cases, it will still produce viable mycelium. It’s better to have too little sugar than too much. A sugar solution that is too powerful will not allow anything to grow in it.


After you’ve chosen your preferred method or the easiest for you, it’s time to mix.

You can heat or cool water to aid in faster dissolving.

Cover the top with aluminum foil. Place the jar in a pressure cooker. Slowly increase the pressure to 15 PSI. For around 15-20 minutes. Caramelization can occur if you use Karo/Honey for longer than 15-20 minutes

Let the pressure cooker cool down before you take it out.


A small hole can be made in the top of a container to accommodate a needle syringe. Half pints are best. Now, put a small amount of silicone sealant (preferably transparent) on each side.

Make sure it’s at least a centimeter thick all the way around each hole. This is a self-healing inoculation site that allows you to suck up inoculant or add spores without having to open the jar.

The spores will be trapped in the vacuum created by tightening the band on the jar before it is pressure cooked. You should only puncture the injection site quickly.

If the band is left loose, the pressure cooker will not seal. Before inoculation, you should wipe the silicone injection site and needle with alcohol.


Before sterilization, some people add crushed glass, marble, or stone to their jars. Shaking can be used to remove the mycelium that may form in the jar. This is why needles with a gauge of 18 or less are chosen.


Honey/Karo can be sterilized in the microwave. You should add more water to the mixture to prevent it from boiling during heating, which will result in more concentrated sugar (which is not possible in a pressure cooker). In the microwave, use metal bands.

Metal lids are available alongside plastic lids. Avoid putting thin metal, such as tinfoil and syringe needles, in the microwave. Toss the liquid into a pot and bring it to a boil. After that, reduce the heat to low/defrost for around 15 minutes. Remember to keep the cap on! Allow it to cool for many hours in the microwave.


Some sediments can remain after the material has been removed.

This can be fixed by opening the jar and filtering the liquid through two coffee filters. Once the liquid is filtered, put it back in the container, cover it with a filter lid, and pressure cook once more.

You can pour the liquid into a separate jar and leave the sediment behind. The sediments are safe, however, they could be confused with mycelium development. It’s preferable to see visible progress. After a few days, honey can induce proteins to sink to the bottom or even float around. After shaking, these will be re-mixed.


The majority of the oxygen in the liquid will be pushed out during sterilization/heating. Although shaking will speed up the network’s growth, it is not necessary to hook up airflow to jars. If you have a filter patch, be careful not to get it. Contaminants may grow through the filter as a result of this


If you do not have an incubator, keep the plant at 82-86F or in a dark area. In a week, they’ll start to show signs of growth. However, they are fully grown by the third week. Some people can see growth in a matter of days, while others take three days. You can use it immediately after it slows down or stores it in the refrigerator.


Liquid cultures can be stored for 6-8 months in the refrigerator. As the mycelium can handle it, a little H2O2 may be added. This will help prevent contamination.


The solution may turn yellow if you leave Honey or Karo on your computer too long. This is called caramelization. This is usually caused by overbaking sugars. It can cause little to no growth. It is possible to still grow a culture in this case, but it is best to start over if you are unable to get spores.


If you don’t own a pressure cooker, you can boil water. Bring water to a boil. Boil the containers at least for 20 minutes.


  • 1 gram of water weighs 1 ml
  • 1 tablespoon of dextrose weighs ~10 grams. This could vary slightly.
  • A tablespoon of light malt extract weighs approximately 10 grams. This may vary slightly.
  • 10 ml honey equals 14 grams
  • 1 tsp (5ml), honey = 7 grams
  • 1 tbsp (15ml honey) = 21 grams

You can look at my Lobster And Mushroom Recipe If you’re interested.

Karo Syrup Liquid Culture Recipe

Dextrose Liquid Culture Recipe
Dextrose Liquid Culture Recipe


  • 500ml of grain water – This water is leftover from making popcorn kernels for grain spawn. If you’re making your first attempt, boil the potato till it is cooked. Do not leave behind any solid residues. Consume the potato.
  • 1 magnet stirrer, or piece of glass the size of a marble 0ml Karo light corn syrup, clear, with vanilla, is good, -4% 1 magnet stirrer, or piece of glass the size of a marble


It is advised that you use a canning container. The size of the liquid culture required will determine how large you need it. Check for ventilation and an injection port on the lid.

Fill the jar with the ingredients. For 15-20 minutes, pressure cook at 15 PSI with a magnetic stirrer.

Once the mixture has cooled fully, inoculate it with liquid culture or clean culture on a piece of agar. At least once per day, stir the mixture. Make sure the lid is properly ventilated.

Take a peek at my Best Lobster Mushroom Recipe if you’re interested.

Cordyceps Liquid Culture Recipe

Here is the best recipe for cultivating cordyceps militaris. This is a great place to start for a beginner. You can adjust the recipe as you go along.

Liquid Culture


  • Recipe for 4 Pint Jars
  • 2 cups water
  • 1 cup wheat berries
  • 2 teaspoons of sugar
  • 1 teaspoon malt extract
  • 1 tsp Frontier Nutritional Yeast (Recommended)
  • A third of a teaspoon of Azomite rock dust
  • Fill the jars with dry grains first. Per jar, 1/4 cup


Combine all dry ingredients with water until well combined.

Each jar should contain 1.2 cups of broth

Cover jars with foil and close them.

For 1 hour, pressure cook at 15 psi

Before inoculating, let the jars cool down completely.


These items may be helpful in the cultivation of cordyceps so I have listed them.

Containers – Cordyceps Cultivation containers. These containers are used extensively in Europe to cultivate cordyceps.

Liquid Culture – Cordyceps Militaris Liquid Culture. This will provide enough to get you started, or to refresh your source. Cordyceps can age and will need to be re-started. This is an option unless you are interested in breeding new strains.

Kit – Cordyceps Growth Kit. You don’t need to invest a lot of money to grow your own plants.

Potato Dextrose liquid Culture Recipe

Today, I’ll be writing about how to make your own liquid culture for mushroom growth.

Liquid culture is a liquid mixture of nutrients that will aid the mycelium in its growth. This is a very efficient cause. With very little liquid culture, you can inoculate directly large quantities of soil or spawn.

Let’s get started making liquid culture!

Potato Dextrose liquid Culture Recipe
Potato Dextrose liquid Culture Recipe

Liquid Culture

I used a base that you can buy at the designated shop, ready to be diluted in water. It is called PDA (Potato Dextrose Agar). Although I didn’t purchase it, I made my own version. It is still valid, even if it isn’t as effective.

After boiling 4 potatoes in one liter of water, I then cooked the potatoes for a while and then ate the potatoes. Mycelium is now hungry for starch and other nutrients. Make sure to filter the water using a piece of cloth.

Then I added 4% of bio honey (don’t add more than 4%) as too much sugar can kill the mycelium. I also added a little bit of dried potato starch (0.5%), I think it was about one teaspoon.

I was able to produce around 1 liter of liquid culture. I sealed it in 4 jars with 250ml each of LC. The jars are large because the mycelium requires a lot more air to develop properly. However, you can fill them up with more air (e.g. Half of the jar.


Although it’s not obvious in the photos, the jars have two holes.

The first is the air filter. To make a hole in the lid, use a screwdriver, a hammer, and a drill. Next, insert a cigarette filter through the filter. Finally, seal the bottom with white silicon. This one should be placed in the middle of the lid.

The self-healing port is the other. This hole is made of silicon and is used to extract the liquid culture from the syringe. After the syringe is removed, the silicon will self-heal (close itself) because it’s so sticky. This one should be placed on the side of your lid to allow the liquid to enter the container.


This passage is almost always the same:

Here is Pleurotus Ostreatus I am doing. For the operation, I should have taken off my hoodie.

All surfaces and tools (plates, cutters) should be cleaned with alcohol. Put alcohol on your hands after you have washed them. To stop bacteria and bad breath from entering the jar, put a cover like a tee-shirt on your mouth and hair.

Next, take a fresh mushroom and flame-smear the cutter if necessary. Then, cut the outer skin off the stem. Finally, take a small, but very small, piece of the inner stem. Pleurotus Eryngii was used for this (King Oyster Mushroom).

Place the small piece in the jar, and seal it quickly.

That’s all! The jars should be kept in a dark, warm place (20-25C), You should notice changes in the liquid’s structure within 2 to 1 month. The mycelium will likely start growing out of the LC at the end of this process.

The best time to use the LC would be before the mycelium starts to grow in the white fluffy jar.

Recipe For Grain Water Liquid Culture

Recipe For Grain Water Liquid Culture
Recipe For Grain Water Liquid Culture

Honey Liquid Culture: How to Make It

A 4 percent honey-to-water ratio is used in most honey liquid culture recipes. After sterilization, inoculate the mixture with mycelium. The jars should be left to incubate at 85-80 degrees for several days, until a white mycelium cluster forms.

These are the main steps:

  • Mix 4% honey/water mixture.
  • The mixture should be sterilized in the jar.
  • Use mycelium to innoculate jars
  • Allow mycelium to grow. Keep shaking the Jar.

Step-by-Step Instructions for Creating Liquid Culture

The instructions for making a 400ml jar of Honey Liquid Culture are as follows.. To increase the chance of making a clean Liquid Culture, we recommend that you make multiple jars.


1st Step: Create a Mixture

Use a screwdriver to make a hole in the lid of a glass jar.

Fill the jar halfway with warm water (400ml) (preferably distilled water).

4 teaspoons honey (approximately 16 ml) to the water.

Mix the mixture well until honey is dissolved in the water.

Screw the lid on and cover the hole with micropore tape or foil.

2nd Step: Clean and sterilize the jars In your pressure cooker, place the jars.

Note: Some people suggest 15-30 minutes because sugars caramelize faster; however, I’ve never had mycelium fail to take to ‘caramelized cultures’. However, I have experienced contamination when I used 15-30 minutes.

3rd Step: Inoculate the mixture of honey and water

Remove the jars from the pressure cooker.

Use alcohol wipes to clean the lid.

To spread the current mycelium, shake the needle.

The needle should be flame sterilized until it glows red.

Place a syringe in the ear and inject 1cc liquid culture.

Take out the syringe, and then flip the micropore tape down.

Incubate the jar at temperatures of 18-20c or 64-68f.

4th step:  Wait

Keep the jar covered with water and stir it daily to prevent the formation of solid, clumpy mycelium masses.

How do you use Liquid Culture?

You sterilize a syringe with boiling water by filling it and then emptying it 3-4 times.

Use Alcohol Wipes to clean the lid of the liquid culture jar.

The needle should be flame-sterilized until it glows red and then inserted into the hole in the lid.

Continue to use the syringe until some mycelium is collected.

As soon as you remove the syringe, cover the hole with micropore tape.

Note: To break down the mycelium into smaller pieces, pump the syringe several times inside the jar.

What are the benefits of using Mushroom Liquid Culture?

There is a lower risk of contamination

Liquid Culture Shroomery claims that liquid culture decreases the incubation period

Mycelium growth is limitless – mycelium doesn’t stop developing once it starts to grow.

What are the drawbacks to using Mushroom Liquid Culture?

Steril working conditions are essential

These are better suited to advanced mushroom cultivation

Liquid culture is ineffable. Your mixture will be contaminated only if you actually use it

The Best Places to Buy Liquid Mushroom Culture

These sites will have liquid culture available for purchase:

True Leaf Market

True Leaf Market is a place where you may buy fresh produce True Leaf Market has a large selection of organic, high-quality seeds, mushroom cultures, and growing kits available.

They were established in 1974 and have been providing high-quality, organic seeds to commercial and home growers for many years. They offer a variety of mushrooms, along with extensive guides and kits.

True Leaf Market products have been certified organic and Non-GMO. Each kit includes detailed instructions that make it easy for you to grow high-quality mushrooms at your home. The website is free to use and has a lot of information for people of all skill levels.

This kit includes:

Block of sawdust fully sterilized, colonized by a vigorous commercial strain.

Very small mister.

Humidity Tent.

Get detailed Growing Instructions.

Prices starting at $27.99

Website: https://www.trueleafmarket.com


Mushrooms.com stocks many gourmets, edible mushroom liquid cultures as well as spore prints. They also offer medicinal mushrooms varieties.

They focus on rare species and valuable species that can be grown yourself. Kits include spore culture kits, which are easy to use and great for beginners. They also have spore prints that can be used by more experienced growers.

This kit includes:

1 x Liquid Culture Syringe

Prices: Starting at $17.95 to $19.50

Website: https://www.mushrooms.com

New generation of mushrooms

New Generation Mushroom Supplies, an online store selling mushroom supplies and kits, is based in Melbourne. You can find a wide range of mushroom spores and liquid culture syringes as well as equipment. If you are looking for all the equipment and liquid mushroom culture, this is the place to go!

This kit includes:

1 x 20ml Liquid Culture Syringe

Prices range from $38.50 to $42.70 (excl. shipping). Shipping and tax not included

Website: https://newgenerationmushroomsupplies.com.au

Fungi Ally

Fungi Ally offers organic and certified organic mushrooms products. This includes spawn and grows kits. There are three types of spawn available: sawdust spawn (plug spawn), and grain spawn.

The kits come in a 10-pound block that is already colonized and ready for growth. Fungi Ally offers a wide range of tools and equipment as well as mushroom extracts, and other mushroom products. You can even find cultivation guides and classes on their website.

This kit includes:

Grow Kits: 1x colonized 10-pound block (produces 3 to 5 pounds of mushrooms).

Grain Spawn: 1x 6-pound bag

Sawdust Spawn: 1 bag of sawdust spawn

Plug Spawn: 1 bag of spawning plugs

Price: It depends on the product. Visit their website to find out more.

Website: https://www.fungially.com (use the coupon: Mindseteco to receive a 15% discount)

Conclusion On Best Liquid Culture Recipe

Liquid Fungi is our favorite supplier due to their wide range of cultures. Their website does not indicate whether kits come with a needle or an alcohol wipe.

They do provide information about each variety’s environment so that you can know what growing conditions to aim for before you place an order.

However, you can buy mushroom liquid culture from any trusted supplier and get your mushroom-growing adventures off to a great start.

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1 thought on “7 Best Liquid Culture Recipe (Oyster, Light Malt Extract, Dextrose, Karo, Cordyceps, Grain Water)”

  1. Hi. You recommend

    “These are the best ratios (IME) for light malt extract LCs:

    but 1 g in 600 g of water is 0.0016. A ratio of 1.6 per thousand?


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