【綿密泡沫的秘密：罐子裡的氮氣膠囊】
桶裝的愛爾蘭司陶特，侍酒時通常利用氮氣與二氧化碳混合氣體，賦予啤酒綿密的泡沫層外觀。市售的罐裝版本也不乏氮氣膠囊設計，然而，氮氣侍酒是相對晚近的發明，並非愛爾蘭司陶特的必要條件。
英倫群島區的某些市售罐裝啤酒，包括英格蘭苦愛爾與愛爾蘭紅愛爾，罐內也可能出現氮氣膠囊。罐裝啤酒中的氮氣膠囊型態不同，但是功能皆在製造有如鮮奶油般綿密的泡沫層。啤酒開罐之後，垂直倒進酒杯，待分層之後再享用。
【Nitro-capsules Typology】
1. Nitro-UFO (from a Boddingtons Pub Ale): Obviously that's what you might think you see after soaking yourself in a pub all night. (Or more frequently like what people say, pink elephants?)
2. Nitro-Ping-Pong (from a Guinness Draught Stout): Beer is human. That is to say, the colored are better at ping-pong. The proof: even the colored beer loves to play ping-pong.
3. Nitro-Fort (fixed in a Wexford Irish-style Crème Ale): Being historically a self-defensive people against the English, they even build a fort at the bottom of an Irish beer can.
