Koji sourdough bread


History of bread in Japan

Breads were brought to Japan as early as 1543 when a Portuguese ship was drifted ashore on the Southern Island of Japan. However, soon after this, Christianity was prohibited due to the strong political motivation and the bread making didn’t pervaded until around 1840. Interesting enough, it was again from the political reason why bread was brought under the spotlight. When Opium wars arose between China and Britain, Japanese government concerned that Japan could also be the target of invasion and started preparing the country against attack. Japanese staple food has been rice, but in order to feed soldiers, it need to be cooked. The government thought bread is the better option to rice as the vapour from cooking rice let the enemy know the location of military camp. Also bread is easier to carry and preserve longer. The military general Taro-zaemon Egawa (江川太郎左衛門) who instructed the development of bread making facility and skill is known as the originator of bread in Japan. 

     The popularity of bread kept soaring after the crisis and Kimura-ya, the oldest bread bakery currently operating, opened in 1869. Kimura-ya developed Sakadane yeast which is cultivated using rice, koji and water. This can be re-phrased koji sourdough yeast as during the cultivation, lactic acid bacteria is also fed. It was quite natural that the company focused on sake yeast as it was most widely available source in Japan.

Koji sourdough bread

     Sake yeast was gradually replaced with bread yeast which is more convenient for modern life. However, there are still bakeries stubbornly follow the tradition and produce koji sourdough breads. The breads baked with koji yeast have subtle sake-like (or slightly cheesy) flavour. They are fluffy, yet chewy and preserve better (stay soft longer) and less likely to become moldy. It is easily digestedas well. Aforementioned Kimura-ya is one of these bakeries and featured in Channel 4 program “Paul Hollywood eats Japan” and was highly praised by Paul.

How to use koji sourdough starter

     Koji sourdough starter is very easy to make. All what you need to do is to mix cooked rice, koji and lukewarm water (roughly in the ratio of 2:1:2) in screw top jar and leave it in the warm place (around 27℃) for 24-48 hours until the volume is doubled. Once the first  starter is ready, propagating it to the next batch doesn’t require time. I use this starter about 10% of flour weight and adjust the liquid volume (subtract the weight of the starter from the liquid in the recipe).

Enjoy koji sourdough making!  

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