Furthermore, the number of ice manufacturers who can produce ice from naturally freezing water in winter the same way as natural ice forms and then stocking the blocks of ice in an icehouse until demand occurs, have declined.
さらに天然氷のように冬の間に暴露で凍らせておき需要があるまで氷室（ひむろ）でストックできる生産者も減ってきている。