How to choose a thermos for mate

Steel, capacity, pouring spout and how long it keeps the heat: what to check before you buy.

A good thermos keeps your mate going all afternoon. Here's what to look for.

Make it stainless steel

Double-wall, vacuum-insulated steel thermoses keep the temperature best and survive knocks. Glass-lined ones also hold heat well, but break with a single bump.

Capacity

500 ml (17 oz): for drinking on your own or short outings.
1 liter (34 oz): the classic, enough for a good round.
1.2 liters (40 oz) or more: for long rounds or trips.

The pouring spout

It's a lid that lets out a thin, controlled stream. For mate it's the most important part: pouring a thin stream keeps the yerba from washing out and scalding. If your thermos doesn't have one, you can buy spouts separately.

How long it keeps the heat

Check how many hours it promises. Good ones keep the water ready for mate for 12 hours or more.

Care

Rinse it after use, let it dry with the lid off and, every now and then, clean the inside with hot water and baking soda.