The traditional method of making sake is declining as breweries are finding it difficult to recruit “toji” workers who stay overnight to monitor the condition of the rice wine.

Japan’s aging population and a shrinking pool of workers has forced companies to improve the working environment, and the sake brewing industry is no exception.

Breweries are now introducing Internet of Things (IoT) technology so that workers don’t have to stay up all night at the brewery.

Saito Shuzo Co. in Kyoto’s Fushimi Ward, a long-established brewery that started sake production in 1895, conducted trial operations of an IoT-based system to check the brewing tank temperature once every hour with a sensor and send the data to a computer in the brewing plant by radio between February and mid-May this year.

It is important to properly control the temperature of rice wine for a whole month after the rice has fermented to ensure higher quality brew.

The monitoring system sends e-mails to brewery officials when the sake temperature exceeds the predetermined limit. It also allows them to check the temperature changes with their smartphones when they are away from the plant.

By using the technology, developed by online system design firm Ratoc Systems Inc. in Osaka, working hours on Saturdays and Sundays as well as night shifts can be reduced, according to Saito Shuzo officials.

Although most of large brewing companies have introduced special tanks designed to automatically control the inside temperatures, not many small and midsize breweries use such systems as they are expensive.

Under a traditional method, brewers known as toji spend the night at brewing plants to monitor the progress of fermentation and the temperature in autumn and winter.

While most of those who take up toji work are full-time farmers who have no agricultural work to do during the winter, the work pool is declining and becoming increasingly elderly.

That trend has resulted in a 40 percent drop in the number of seasonal workers in the rice wine brewing industry from 15 years ago. As of the end of March 2016, only 2,600 migrant workers are involved.

Last year, Saito Shuzo, for example, stopped hiring them.

“Lessening the burdens on workers by reducing night shifts and work hours on holidays is essential to enable our permanent employees to solely produce sake,” said Toru Saito, president of Saito Shuzo. “I hope it (the monitoring system) will help such efforts.”

The president said his company has already decided to fully introduce the monitoring technology.

Shoutoku Shuzo Co., another brewer in Kyoto, also adopted the system on a trial basis in March.