Standard is the criteria, the ideal in terms of which something can be judged. I don't think we need a dosing standard. Standard dose is whatever tastes best to you or if you are business what tastes best to your customers...

As far as I know, the trend to updosing traces back to David Schomer, who spent some time in Italy and then came back to open his cafes and write his book. Although Schomer implies that he brought knowledge back with him from Italy, what he did in Seattle bears no relationship whatsoever to what is commonly done in Italian cafes, with the possible exception that an espresso machine is used in both countries.

After a period of time Schomer's approach to dosing became more or less standard practice in most well known N. American cafes, and now also in some northern European countries, but not in Italy.

Briefly stated, "espresso" is a drink in Italy, and a process for making a beverage under pressure in N. America and some other places. Whether you prefer one of the resulting beverages over another is a topic that on HB seems to rapidly degenerate into the verbal equivalent of mud wrestling, and I suspect that most people here have already stated their opinion(s) on this topic multiple times before. Dan gave a link to one of the prior threads, and a little searching will pull up additional topics with repetitive posts.

ken

Leaving Schomer and his reasons aside, I think there is an espresso equivalent of the upsizing in milk drinks and that is a vogue or preference for a fuller body and mouthfeel in espressos and ristrettos, which of course comes at the expense of a less nuanced or layered taste profile.

There could be many entertaining explanations

When preparing espresso, most of the time, it is for a single person. And the single shot basket is not very popular (and harder to use for newbies), so new people in front of the machine will try to get a single using the double basket to self teach themselves. Also, espresso came to America but America did not change the cup size as it was part of the ritual. America imported the machines as a novelty but it had to self teach itself. If there were bigger espresso cups, perhaps the up dosing trend would not had happened, and perhaps people would have kept the same coffee to water ratio. However, they grew a new appetite for the up dosed drink at the same time of 'discovering' the new drink that came out of the newly imported machine. And like the chicken out of the egg, they made the connection of the found flavor with up dosing ratio. But when they sought to defined it (since it was new), in the mind, the flavor was already a double in a single. That was never questioned. In the American market, espresso was introduced as a specialty competition drink since its found potency posed challenges. The potency was a distinctive quality sought to bring attention. It was hard to balanced such a drink (single in a double) and the competition purpose was born. But why the American market did not make the cup double the size to start with? Could have been they accepted the cup size as a symbol. It would have suited many practical aspects.

Cheers

Over here in the UK it's common practice to just set things up for a double in the chains with high staff churn, but that also involves using the double portafilter. When someone asks for a single only one cup is used, the usual volumetric button pressed and one of the spouts simply pours straight into the drip tray.

But I don't think this is a phenomenon with just one cause. I believe others posting here have been correct in also identifying the trend for SO beans and lighter roasts, often by self-taught roasters using very sophisticated machinery that can make very fast changes, but not always with the beneficial effects anticipated....