A fermentable sugar is something that a yeast or bacteria uses as an energy source. Grains (cereals) such as barley or millet or rice have a lot of starch. To be useful they have to be broken down into smaller pieces called simple sugars.
Filamentous fungus are a specific type of microbe capable of doing this. Either alone or in different combinations koji (Aspergillus and another specific fungus called Rhizopus) does this by creating enzymes that power or catalyse this process. They can break down lots of things.
Specific types of cultures or microbes that either include koji or are entirely made up of koji are used. They break things down into smaller pieces by creating many different types of enzymes.
Koji can break down starches, fats, proteins and other things from organic sources. Usually this is done through a process called hydrolysis, which just means water is involved in the process.
Koji (A. oryzae) is better at – and does not produce harmful toxins like a close relative Aspergillus flavus – at breaking things down. The breakdown enzymes that brewers are mostly concerned with are amylases, glucoamylases, pectinases, proteases, and lipases.
Koji is genetically and specifically capable of making hydrolytic enzymes and enzymes that move sugars and other substances around during fermentation. Remember that without enzymes everything would need more energy that would ever be available.
You can also use koji in it’s extracted form as well as a whole substrate such as koji grown on rice to make pickles, sake, shoyu koji, amasake and more.
Aspergillus oryzae has been specifically selected out over many years so that the strain we use typically knows what to do. When a great batch of sake was made, brewers used the same strain that had made that batch to create a new one with the same desirable koji properties.
Malting is done by sprouting or germinating a grain. Many different kinds can be used including rice, barley, and corn. All grains contain a lot of starch. The serve as a seeds energy source.
If you expose dried grains to water and the right temperature they will sprout, creating enzymes to break down starches for the grain to grow. This is called malting. Very useful for a plant until there are leaves that can get energy through photosynthesis. But brewers get the. enzymes before they are spent on growth. They are used to break down their starches.
As long as some fermentable sugars are available we create a moromi or wort to make alcohol. Whether you are making beer, sake, vinegar or soy sauce, wild yeasts or specifically selected yeasts turn the sugars into alcohol, carbon dioxide and heat.
The heat comes from the microbes doing their job has to be carefully controlled during koji making, as well as during the process of making beer or sake or another product. There are different ways this can be done, as there are different types of koji better for specific outcomes such as sake or shoyu。
But whether it’s sake or beer – which actually usually uses malted grains that produce the same type of enzymes as koji – the same saying applies to all microbrewing: “Ichi koji, ni moto, san zukuri”. First koji, second the Moto, third the fermentation.
We are having our last #KojiFest2019 event and the first #Zymes2020 event at Fifth Hammer Brewing in Long Island City on December 16th, 2019. You must pre-register for the event.
In the meantime, we will be publishing this 16 part series about how to make koji and extract it’s enzymes, and how to use what the koji is made on – a substrate – directly in brewing or baking or miso or sauce making.
Enzymes serve two roles. They break down things such as tiny bits of food that you eat into smaller things. Or they combine smaller things like the amino acids from proteins into bigger things. Enzymes make possible every vital function of living things. Sometimes enzymes already exist in living things like your gut.
But most times they are used process things into food or drinks. Without the enzymes in malted barley, for example, it’s unlikely that either bread nor bread would exist as they do today.
Enzymes from koji have been used in European and American food manufacturing for at least 100 years now. We will get into what they have sometimes been combined with (other microbes, yeasts, techniques).
They are very safe to use, but you must be careful when handling them. Anything that can tear through grains or the muscles of animals should not be handled carelessly (see below).
“Curiously enough this tiny and important hustler has scarcely attracted attention in the Occident, and this fact made me determine to work for it’s introduction to industrial use in the United States”
This quote is from a paper printed in 1914 in The Journal of Industrial and Engineering Chemistry (Vol.6, No.10). The author is Jokichi Takamine. He’s talking about koji (A.oryzae).
One of the things he was trying to do was to address the concerns of brewers and maltster – the people that make sprouted grain malt for beer – about the cost of the ingredients to create diastatic enzymes. The price of barley could vary. considerably from season to season. He had earlier filed a patent in the US to do so, “in a process not hitherto practiced”. He succeeded.
On February 23, 1894, a patent was filed in the US : “The object of this invention is to prepare and manufacture diastatic enzyme, or soluble ferment in a concentrated form which possesses the power of transforming starch into’ sugar for use in various industries, by a process not hitherto practiced, and in a very economical and practical manner.
My invention is based upon the utilization of the property possessed by certain fungi during their growth on proper media of producing diastatic enzyme.“
Typically, barley was malted. Malting creates diastatic enzymes. But Takamine thought of using something that was pretty much being thrown away, yet which could produce way more diastatic power and be less perishable.
Despite some violent outbursts suspected to have come from the maltsters at the time afraid of losing both money and their businesses, the brewing and food manufacturing industries in in the US ultimately adopted the use of enzymes, sometimes malt from barley or other grains for beer, but overwhelmingly from fungal enzymes from Aspergillus in baking, food processing and medicine.
Today both brewing supply houses and enzyme companies sell specific enzymes from many fungus, molds, even bacteria but different types of Aspergillus (koji) are used extensively throughout the world.
Takamine’s substance became an amazingly useful drug used to help people digest food. Enzymes are a very big deal. You can make your own as described below, but be aware that a small microbrewing operation can very quickly become larger than the brewing or refrigeration or heating capacity of your space.
How to Make Takadiastase
- 5 gallon container
- 2 1/4 pounds (1024 grams) wheat bran
- 3 gallons lukewarm water (9000 grams)
- 1/2 cup (138 grams) coarse 100% NaCl salt
- Aspergillus oryzae spores (1 gram pure spores)
Taka-Diastase is made with Aspergillus oryzae, the hardest working fungus in the world. It is made on wheat bran. We milled off the bran from winter wheat berries – they have tasty bran, but other types of wheat brans work well – but you can buy it in sizes from one to 50 pounds.
We suggest you start off with 2 and 1/4 pounds (1024 grams) of wheat bran. Remember that wheat bran is unlike wheat berries or even flour. It is typically very light when dry and flies everywhere.
This is especially important when you are about to harvest (or dekoji) your finished Taka-Diastase. Unlike, say, rice koji, you have to consider how to reduce the temperature without fans after a certain point.
As the temperature decreases and it dries out, fans will blow it everywhere. I recommend either using wood that can absorb a lot of water – when you reduce the heat of something the water will either evaporate in the air or soak into whatever it is on.
We often use lots of cloths when making bean or rice koji. Whatever you chose, be prepared to have lots of cloth changes or at least one other wooden to container to transfer the koji into as it dries.
Unless you are going to use it almost as soon as it is finished – we sometimes have a salt brine ready to throw prepared koji into while still warm – you have to dry it out. Otherwise, it will continue to grow.
And a moist pile of amino acids are a feast for all the wild microbes that hang out in the air.
Did any of this seem complicated or overwhelming? Most people don’t ever make their own koji. You can easily buy it. In 35 pound boxes rice koji can be quite reasonably priced.
But if you only want to make a pound or two of koji, it’s cheaper making it yourself. You can also buy the powdered enzymes. But here are basic guidelines to make any type of koji. (Part 2, next post.)
The Awesome Power of Koji
There is actually a large body of evidence on why bread and pastry bakers, farmers, and koji growers must be very careful about both inhaling aspergillus spores, as well as getting it on their skin. We will talk about that as well during the year long series, just remember to always wears gloves and masks when dealing with enzymes.
It makes sense that something with the power to break down meat, fish, or very hard grains would be something to treat with caution. Sometimes things that are obvious to someone working in a professional, including the pharmaceutical industry and food manufacturing industries where Aspergillus and enzymes are used extensively, are not well known or made public.
Please be careful when handling enzymes created by anything, either from a sprouted grain or a fungus. Here are is a very small sample of some of the things that can happen when inhaling spores or enzymes from Aspergillus oryzae. As in the koji we are describing how to make.
- Valdivieso, R & Subiza, Jose & Hinojosa, Mariel & Carlos, E & Subiza, E. (1994). Baker’s asthma caused by alpha amylase. Annals of allergy. 73. 337-42. Abstract: Two bakers with bronchial asthma and two with rhinoconjunctivitis are described. Prick and RAST tests were positive with wheat flour in all of them, but the challenge test (nasal or bronchial) with wheat flour extract was positive only in one asthmatic baker. The prick test, RAST, and nasal or bronchial challenge done with alpha amylase extract (a glycolytic enzyme obtained from Aspergillus oryzae and used as a flour additive) were positive in all four patients. Our results support previous data indicating that alpha amylase used in bakeries is an important antigen that could cause respiratory allergy in bakers. It can function as sole causative allergen or in addition with other allergens used in the baking industry.
- Sharma BB, Singh S, Singh V. Hypersensitivity pneumonitis: the dug-well lung. Allergy Asthma Proc 2013;34:e59–64.
- Gerfaud-Valentin M, Reboux G, Traclet J, et al. Occupational hypersensitivity pneumonitis in a baker: a new cause. Chest 2014;145:856–8.