Cider Blew its top!

During fermentation of hard cider, is it safe to stop the fermentation using boric acid?
Cider Blew its top! - Articles

Updated: August 9, 2017

Answer - It sounds like he has not given the cider a sufficient time to completely ferment before sealing. He should measure the sugar content with a hydrometer and periodically take measurements as it ferments until the readings level off to a minimum value. Or he can attach a tube to a fermentation vessel allowing the escaping gas to bubble through a water trap. When the bubbles stop, the cider is done. At this time, the sugar has been fermented to alcohol and very little additional CO2 will be generated.