Is it just me or does that sound like the name of a town in Ireland? Oh right, it actually is the name of a town in Ireland, a little spot on the northeastern coast where this red seaweed-derived thickener was originally harvested and put to use. It’s been used to thicken puddings and custards in that region since at least 1810. Oh, and in Scotland as well. Locals would boil the local weed to extract the long-chain sugars, add borax to the hot solution to make them clump, then strain the whole mess out and dry it to a powder. The process was steadily improved to the point that in 1930 carrageenan became a mass-market product. It’s been a staple thickener for food makers (and some home cooks) ever since.