Not exactly a ritual of drinking a specific beverage, but in Spain, prior to the introduction of coffee, or the popularisation of chocolate, the beverage most commonly associated with breakfast was wine, odd as it may sound to present-day eyes, and the testimonies linking wine with breakfast are very abundant. I'll translate a few cases, as they cover many social strata.

Diego Duque de Estrada, a famous captain who wrote his memoirs around 1640, mentions this passage in them, as many presents were brought to him, bordering on the absolute hilarity due to the absurd quantity of food brought to him: They called for me and said that misser Jeronimo Resti, recognising he was in debt to me sent me that small present so that I could have for breakfast or snack, and the expected me for lunch, and that I would be lodged in his house with as many comrades as I wished [...] The present were two very large baskets of turkeys, capons and much more game, with many different dressings, all in fine silverware. Two more large baskets of excellent hams, and salami. Two more with the whitest and best bread that I had ever seen. Two more of very exquisite fruits. Two deers, two wild pigs, and half a barrel of wine

The anonymous author of "La vida de Estebanillo González" (1646), a picaresque novel, contains this particularly funny moment of Esteban as a heavy drinker: They roasted the sardines for me, and just from the smell of them at the flames, I drank half a dozen cups of wine, and with their taste eighteen more. I asked the hostess how much I owed her, and looking at from feet to head, said:

- You have drank no more than 24 cups, two shillings apiece; had I got 24 patrons of such a good quality, my husband would soon be a knight twenty-four of Seville.

I paid what she requested, and said that it was a short breakfast for what I accustombed to drink.

Francisco Santos, in Las tarascas de Madrid (1665), gives us this quote, with wine and breakfast: The butler hears them, and comes to greet them with courtesy, and so that they will know him (because he knows what people are those) and sends for wine for them to have breakfast, as he thinks they are going to need it.

Juan de Zabaleta, in El día de la fiesta por la mañana (1645), has a funny character make this remark about the importance of a good breakfast: The nobleman commands to have some biscuits and some good wine for breakfast. This is better for having good blood than being a descendant of Xerxes

Pedro Calderón de la Barca, in his remarkable Entremés de las carnestolendas (1646) has this quick passage between Luisa and the gracioso: [Luisa comes out with a plate and a jar of wine].

LUISA- Here you have your breakfast

GRACIOSO- It's little, but enough for onw.

These are but a few examples to illustrate the fact that breakfast in the Spanish Golden Age involved having wine, which is prior to the popularisation of coffee, and even the popularisation of chocolate, which was expensive and not something statistically significant, as it was for the upper classes. An important remark has to be made, and it is the fact that wine, as far we know, was less strong in alcoholic content, and would frequently be served watered down. This is not quite a ritual, but rather the ordinary state of affairs.

This is also, of course, strictly limited to Spain, which is my area of knowledge