by Doctor Science
One of the traditional British class markers is whether you put milk in your cup before you add tea, or vice versa. For the past 150 years at least, tea-first has been upper-class, milk-first middle class (or lower). I have a theory about this, which is mine.
In the 18th century it is thought that aristocrats would pour the milk first, perhaps so as not to stain or crack their fine china. By the early 20th century this social habit had reversed: putting your milk in first had come to be seen as an irredeemably middle-class affliction. In Noblesse Oblige, published in 1956, Nancy Mitford refers scathingly to 'MIFs' (Milk in Firsts), whom she defines as being 'non-U' (non-upper class).On the other hand, in Tea Culture Beverly Dubrin says:
According to speculation, the lower classes could not afford high quality porcelain cups, and pouring the milk in first prevented lesser quality earthenware cups from cracking.If Moore is correct that MIF started out as "U", why did the custom switch?
Here's my theory: MIL (milk-in-last) is a better way to get your chosen balance of tea & milk, because if the tea is being poured into a cup from a teapot you don't know exactly how strong or weak it is until it's in your cup. So, as porcelain manufacture improved into the 19th century, the upper classes would naturally move to MIL, to get their ideal cup of tea.
I think the non-U classes stayed (or became) MIF not because of problems with their cups, but because of problems with their milk.
My experience is that if your milk is in any way "off", it will curdle when you put it straight into hot tea, and then you have to dump the whole cup. If you put the milk in first, by itself, you can tell if it's off before you waste any tea. In addition, adding the tea to the milk warms the milk up more gradually than just hitting the cool milk with hot tea, so if your milk is borderline fresh it’s much less likely to curdle when it’s MIF.
Because the Industrial Revolution started in Britain, by 1800 most of the middle classes (who were non-U but could afford tea) no longer were in close contact with farms. Only the Upper classes could move to MIL -- to get an ideal cup of tea, and to demonstrate that they didn't have to settle for milk that wasn't perfectly fresh.
Conversations with Britfriends these days indicate that MIL is more popular with all classes than it used to be, because many Brits now make tea by the cup with teabags. MIF doesn't work with this system because it cools the water too much before the tea is done steeping.
This is my theory, which is mine. I don't know how much MIF/MIL persists as a class marker in the UK, nor do I know how much it was ever one in Scotland. In the US, tea is more often drunk cold than hot, and hot tea is more often served with lemon than with milk. Except for chai, which IIRC only really hit the US in the 90s, and which gets around the whole MIF/MIL distinction by brewing the tea in (diluted) milk.