Water is the default
Horchata is a rice drink. The rice is what makes it look and pour the way it does, and the traditional jug is rice and water with cinnamon, nothing else. That is also how this blend is built, so water is what the panel on the pouch assumes.
If you have never made it before, start there. It is the version you would be handed at a stall, and it is the one that goes with a plate of something hot.
What milk changes
Milk makes it heavier and rounder, and it softens the cinnamon rather than sharpening it. Some households have always made it this way and would not recognize the water version as the real thing.
Almond, oat and rice drinks all work too, and each pulls the glass a little differently. Oat is the closest to milk in body. Almond keeps it light and pushes the cinnamon forward.
Cold liquid, whichever you pick
This one goes into cold liquid and stays there. Hot milk does nothing useful to it and the rice behaves badly in heat.
Same rule as every other pouch: work the powder into a splash first, stir it smooth, then top the jug up. Ice at the end.
If it lands sweeter than you wanted
The sweetening is milled into the blend, so there is nothing to leave out at the counter. What works is using less powder for the same amount of liquid, which costs you a little body but very little flavor.
The other lever is ice. Horchata over a full glass of ice dilutes as you drink it, which some people plan for and some people find disappointing halfway down the glass.
The rice at the bottom
Ground rice settles. A layer at the bottom of the jug after ten minutes on the table is the drink doing what it does, not a sign that the pouch is old or that you mixed it wrong.
Stir before each pour. Straining it out takes the body with it and leaves you with cinnamon water.
The one that gets confused with it
Marzipan sits next to horchata on a lot of menus and gets picked by mistake. It is a peanut and almond jug rather than a rice one, sweeter and rounder, and it does not settle the same way. If somebody at your table asked for horchata and got that, this is why.
Water for the traditional jug, milk for a heavier one, cold either way, and stir before you pour.
