Pathway no. 3 : CULTIVATION OF AMYLOLYTIC FUNGI

This solution uses moulds grown on cooked starch. The mycelia of certain fungi (Aspergillus, Mucor, Rhizopus, Monascus, Amylomyces, Rrouxii, Penicillium, etc.) harbour enzymes that can hydrolyse the starch. The starch granules are subjected to heating in the presence of water (cooking, stewing or steaming). The starch is then exposed to the action of the enzymes, provided it comes into contact with the source of the fungi. The organs of certain plants contain a lot of these fungi: roots (ginger, piper), leaves (mulberry, banana, etc.), buds, stems or bark.

This brewing technique is very old. It was used in Asia, Africa, South and Central America. It has not yet been recorded on the European continent, due to a lack of research on that subject.

 

Aspergillus oryzae (麹)

The method therefore consists of cultivating certain mycelia on dumplings of cooked starch, in order to make dry ferments. This fungi cultivation lasts from one to several weeks, depending on the technique, the source of the mushrooms, the region and the season.The operations, which are quite delicate, are true empirical biotechnology, at least with a traditional method. With cereal malting (pathway no. 2), the enzymatic source is endogenous. It is the embryo of the germ that generates the amylases. With method n° 3, the enzymatic source is exogenous. Human must control all the parameters to successfully inoculate the cooked starch: humidity, temperature, nutrients (starch is necessary but not sufficient), ventilation, and so on.

The dried small loaves, bricks or balls covered with mycelium can, like the malt, keep for a very long time (12 months or more). Called "ferments", they are, like the malt again, the source of a very profitable local or regional trade.

When the beer is brewed, the second stage, the actual brewing, begins. These ferments are added to a cooked mass of starch and intimately mixed with it. The ferments inoculate the cooked starch, which soon liquefies under the action of amylases and ferments under the action of yeast. The cultivation of mushrooms is not very selective, at least in traditional brewing. Along with the mycelia, which have amylolytic properties, come the yeasts present on the plants, in particular the genus Saccharomyces and lactic acid bacteria. But the designation "ferment" (starter in the Anglo-Saxon litt.) should not be misleading: the first function of the beer ferment is to saccharify the starch mass at the time of the actual brewing. Certain strains of amylolytic fungi of the genus Aspergillus or Rhizopus can also initiate an alcoholic fermentation. Conversely, yeasts can also hydrolyse the starch (infra).

Brewing with amylolytic ferment (method no 3)

 

 

 

Some microscopic fungi produce amylases (Aspergillus, Mucor, Rhizopus, Monascus, Amylomyces rouxii, Penicillium, etc.). The method grows the mycelium of these fungi on a cooked starch substrate. These moulds are obtained from plants by bringing some of their organs (roots, stems, leaves) into contact with the cooked starch.

 

When the mycelium has developed, pellets are formed which are dried and preserved. These are the beer starters.

 

To brew beer, they are mixed with a semi-solid mass of cooked starch. These grown mushrooms also have an aerobic metabolism that converts sugars into alcohol. When this mash is sufficiently saccharified and fermented, water is added to get the desired beer.

 

The amount of water added regulates the density of the beer. The fermented mash can be washed out several times, each round giving a weaker beer.

This ancient method has been applied to wheat, millet, rice and tubers throughout Asia. The use of beer ferments has been proven by Li Liu's team as early as the Neolithic period of Yangshao (7000-4000 BC). era) in the middle Huang-He basin, at Mijiaya and Dingcun. The method n° 3 is the preferred way of Chinese brewing since the Shang dynasty (1766-1122 BC). It has been since and until today massively used for rice beers (China, Korea, Japan, South-East Asia), wheat-millet beers from the Tibetan-Burmese cultural area (Tibet, Nepal, Sikkim, Bhutan, Burma), and traditional beers from South-East Asia. The supply of exogenous enzymes compensates for a lacking (polished rice) or too weak (wheat, millet) endogenous enzymatic power. It should be noticed that this traditional method is applied in the upper Congo basin (Songola people). It can also be found in the Caribbean in the 18th century, although lost and forgotten since the Spanish colonisation of this region.

Some filamentous yeasts (Endomycopsis fibuligera) also exhibit an enzymatic power (glucoamylase + alpha-amylase). They are cultivated in the Philippines on a substrate of cooked rice or millet to make a ferment (bubod). This inoculum is then used to brew rice or millet beers. It is even used to start the fermentation of a local wine made from palm sap (palm wine) (H. T. Huang, 2000: 272-274 and 278-282), or sugar cane wines (H. Sakai, G. A. Caldo, 1985: Microbiological studies on bubod, a fermentation starter in the Philippines, Philipp. Agric. 68, 181-188).

Nowadays people drink jiu from rice or millet in China, taekju (or yakyu) in Korea and its cousin the sake in Japan. In North India, people drink rice beers: pachwai, ruhi, murcha, bakhar, madhu. In Tibet chang (barley beer), ragi in Indonesia, brem in Bali and sato in Thailand, all three based on raw rice. All these traditional beers share in common a brewing method using the technique of beer ferments.

This technique concerns more than half of the volume of traditional beers brewed in the world (jiu, sake, ragi, brem, ...). The other half is brewed with the western technique of malting, by the germination of cereal grains. This geographical separation of brewing methods is a relatively recent historical fact. It started about 2 millennia ago, for both technical reasons (progressive domination of rice in Asia) and relatively complex social reasons.

The technique of beer ferments became industrialised, like that of malting, from the 18th century. It has followed the same technological developments as those governing the western brewing industry: growing volumes of brewed products, streamlining and standardisation of brewing processes, scientific research, introduction of the laboratory and its tools, financial investments, etc. Describing these beers as "traditional" (vs. the "true modern beer" = the industrial lager) is misleading and derives from an ill-founded Western vision.

 

This brewing method is also used on other continents: in South America and Africa. To date, only Europe does not seem to have developed it in antiquity or in our time. But hardly any archaeological projects or historical studies have seriously researched it..

In tropical Africa, the Songola living on the upper Congo River have mastered sophisticated brewing techniques studied by T. Ankei (The Songola of the Congo River and their ferments (starter) for beer brewing). They include the production of beer starter cultures by growing amylolytic fungi on cooked cassava or maize. Once covered with mycelium, the cassava pellets are dried and pulverised for later use as a saccharification starter. These dry ferments can be stored for a long time. This method is also used by the Iraqw in Tanzania.

In South America, Terry Henkel documented in 2004 the actual brewing of a cassava-based Parakari beer by the Wapisiana Indians of Guyana (Henkel, Parakari, an indigenous fermented beverage using amylolytic Rhizopus in Guyana). Their brewing method uses beer ferments grown on cooked cassava. A strong variety of cassava-based cachiri is brewed in this way by the Wayana Indians of Guyana and Suriname. This technique is older. In the 17th century, the brewing of sweet potato beer in the Caribbean area involved the use of mushrooms for some of the high alcohol variants of this type of beer.

Therefore, the beer ferments are not specific to Asian regions as is often believed or read.

 

 

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01/04/2013  Christian Berger