A few things to consider and a quick word on a pet peeve...
In the 1860s, drinking water was only beginning to be filtered, purified, and treated for the various water-bone illnesses we know today; so, the Citizen had different drinking habits entirely.
The Citizen, also, lived and traveled in a different social-hospitality construct.
So, your Citizen would have had a drink before s/he left their home, would have been offered a beverage when they visited friends, bought a beverage at an establishment, and drank from creek to hand with a glance for obvious unhealthy pollution (like a rotting carcass). The Citizen would also have thought little of going up to a house, knocking on the door, and asking for a drink... which they likely would have been provided.
The Citizen would also have been drinking a lot less than we do today. When water is suspect and beverage availability uncertain... one tends to simply not drink. Not an option for the modern interpreter at a hot event.
Very little of the above happens at events, save offering a drink to “visiting” friends and the occasional beverage establishment.
So... we must look to do something that is outside of the everyday experiences of those we portray... bring beverages along on a “quick day trip”.
Thus, in researching, we will look to the occasions our Citizens did have to bring beverages along... hunters/sportsmen on day-long excursions, picnics, and bought-beverage packaging... and also, long voyages with uncertain re-provisioning, such as westward migration.
So... look to your event. If you are portraying your own home... grab a bucket to get water from the centralized event water source and serve it from pitcher to glass. If you are “in town”... look towards a flask, bottle in a basket, or possibly a sportsman’s canteen. If you are a commission agent, Army-associated, or other person who goes in to the situation knowing water access will be uncertain... look to sportsman’s canteen or bought beverage packaging.
The Things you carry support the Story you tell as much as the clothes you wear and the physical space you create. Not just “any old thing” will do... it may say something about your portrayal you don’t intend.
A few more tangents ...
***Iced tea was seen among beverages for invalids. Hot tea was the method for healthy adults. In hot, humid weather... the idea of hot tea leaves us UG! ...so... lemonade, fruit vinegar, switchel, an infusion of mint and ginger sweetened to taste and served over ice... lots of choices, just not iced tea.
***Switchel... I’ve been looking for almost a decade and have not found published recipe or instructions that substitute honey for molasses or include honey in addition to molasses. When I request of the Hive Mind, I get lots of “well, it just makes sense, they used honey as an alternate sweetener so often.” Agreed, it was common substitution for sugar... but I can’t find it in direct reference to switchel use. If anyone can... please share.
***Yes, “mucket” is a military and sportsman item... so again, if you want to use one, have your sportsman catalog handy or expect to remind your military fellow participants that they were available private purchase at the period equivalent of Colman and you were not stealing from the dead. Keep in mind, they have a lot more fun accusing you of stealing from the dead.
***They were less likely to drink from the storage container. There’s a reason Mother scolds you to use a glass.
Please see my blog archive for recipes and further info on beverages.