The heat retention in the GSI Outdoors Microlite 1000 Twist ($34.95) insulated bottle is so effective that it requires planning ahead. With 18 hours of heat retention and 32 hours of cold retention, you can count on the temperature of the contents to hold steady all day; just don’t expect to be able to drink your coffee for the first few hours without burning your mouth. As an insulated bottle, the GSI Outdoors Microlite 1000 Twist won us over in every category but one — read on to find out what we’re suffering through.
What I Liked
Insulation
The most important thing in an insulated bottle is, of course, how well it insulates. In factory conditions, the GSI Outdoors Microlite 1000 Twist will supposedly keep your hot beverages hot for 18 hours and your cold beverages cold for 32 hours. In our field testing with temperatures ranging from seven degrees Fahrenheit to -5 degrees Fahrenheit, we gathered 12 hours of data from three insulated bottles and one non-insulated bottle as a control.
The other two insulated bottles were the Yeti Rambler 30 oz Tumbler with double wall plastic Magslide© lid and the Klean Kanteen 32 oz Insulated Growler with Swing Lok© cap (no longer sold on the Klean Kanteen site). Each bottle was filled with boiling water (212 degrees F) and tested after 3, 8, and 12 hours.
The GSI Outdoors Microlite 1000 Twist was a clear winner, even though the Klean Kanteen claims it will retain heat for 30 hours and cold for 80 hours.
In practice, after a number of frigid Minnesota days at the Sandstone Ice Park, I learned that if I wanted to drink my coffee, I had to temper it with a splash of iced coffee. Otherwise, it stayed too hot for me to drink without scalding my mouth. The insulation in the GSI Outdoors Microlite 1000 Twist works so well that if you’re going to drink the contents within 8 hours of filling it, you should make sure the liquid is drinkable when it goes in.
That said, this means that the Microlite 1000 Twist lets you plan easy comforts far ahead in your outdoor adventures. Let’s say you’re winter camping and know you’ll want a hot drink or hot soup at the end of a long first day: fill the thermos with boiling water or scalding hot soup before you leave, and 12 – 18 hours later, you’ll still have hot water. Or let’s say you’re in hot conditions: fill the the GSI Outdoors Microlite 1000 Twist with cold water and ice, and you’ll still have a liter of cold water the next day after everything else (you included) has baked in the sun. That ice water is going to feel great on your second day of summer adventure.
Construction
The size and shape of a Nalgene, the Microlite 1000 Twist holds a liter of liquid and still fits into any pack pouch the crowd favorite non-insulated water bottle does. With 2mm stainless steel 18/8 walls, it’s incredibly lightweight for its insulating power. The screw cap top seals easily and tightly, protecting against both leakage and heat loss, and unscrews just as easily with gloves on. The lid supposedly has a “leverage enhancing lobe making frozen bottles easier to open,” though I honestly didn’t notice much of a difference. The bottle is pretty durable, too, having been hit by falling ice from 40 meters with no real visible damage.
Price
Even though the Microlite 1000 Twist outperformed the other bottles in every technical way — weight, temperature retention, size — it is less expensive than the other bottles of similar caliber. At time of writing, it was $34.95 compared to Hydro Flask at $44.95, Yeti at $49.99, and Klean Kanteen at $54.99.
What I Didn’t Like
Washability
GSI Outdoors recommends hand washing the Microlite 1000 Twist only, compared to Yeti and Hydro Flask bottles, which are dishwasher safe. That’s it. That’s the only thing.
Final Thoughts
In full disclosure, before testing the GSI Outdoors Microlite 1000 Twist, I was a diehard Yeti groupie. After spending a season on the ice with the Microlite, it’s my go-to bottle. If you’re searching for an insulated bottle and you can survive hand washing — I know, really roughing it here — there’s no better thermos on the market right now than the GSI Outdoors Microlite 1000 Twist.
