Thermal Cups Comparison | Boating Magazine

Thermal Cups Comparison

Choose the best thermal cup to take boating.

Toby Keith needs to write another song because Yeti and a dozen other thermal-cup brands have made the red Solo cup do the “Boot Scootin’ Boogie” right out the door. Thermal cups have been around a long time, but Yeti made them popular last fall and, in a most unexpected miscalculation, ran out of them just before Christmas. That left room for Engel, Stanley, Thermos and others to snap up some market share. Is there a difference? Well, yes … and no, and for two reasons we felt a definitive test of these re-energized chalices was in order. First, we applaud the reuse of any container that eliminates the waste of plastic, cans or bottles. Second, we’re down with any old jug that can keep our refreshments refreshing all day long.

 

Yeti 10-ounce Lowball

Thermal Cups

Bill Doster

Yeti 10-ounce Lowball
$25

It’s slightly big for a rocks glass, and if you like your spirits straight, don’t expect melting ice to soften them for you. Add the amount of water you want — the drink will hold that temperature longer than it would in a lowball glass. Yeti didn’t make the Lowball to fit a standard cup holder for good reason: This is for dockside refreshment. An optional lid — the same one that fits the 20-ounce ­Rambler — is $5.99, and it’s a worthwhile investment.

Extra point: It’s chunky dimensions feel good in the hand, and it won’t sweat and leave a ring on that teak cockpit table.

Initial Ice: 5.6 oz.
Ice Lost at 4 Hours: 23%
Ice Lost at 8 Hours: 48%
Exterior Temp at 3 Hours: 73.7°
Hot-Liquid Heat Retention at 4 Hours: 76%

Ice Lost at 4 Hours: 2/3
Ice Lost at 8 Hours: 2/3
Ambient and Exterior Temp at 3 Hours: 3/3
Hot-Liquid Heat Retention at 4 Hours: 2/3

Total: 9/12

 

Yeti 20-ounce Rambler

Thermal Cups

Bill Doster

Yeti 20-ounce Rambler
$30

There are no discounts on a Yeti, and, in fact, before-Christmas scalpers listed some on eBay at a premium of a hundred clams. The 800-pound gorilla of thermal cups is made from 8/18 kitchen-grade stainless steel. Double-walled construction only works because there is a complete vacuum between the layers, inhibiting heat transfer. Even the clear plastic lid is BPA-free.

Extra point: A standard clear-plastic lid with a silicone seal presses tightly into place with a sipping slot for knocking back the contents. At 20 ounces it’s almost enough to satisfy my morning-coffee habit.

Initial Ice: 9.9 oz.
Ice Lost at 4 Hours: 7%
Ice Lost at 8 Hours: 23%
Exterior Temp at 3 Hours: 73.7°
Hot-Liquid Heat Retention at 4 Hours: 81%

Ice Lost at 4 Hours: 3/3
Ice Lost at 8 Hours: 3/3
Ambient and Exterior Temp at 3 Hours: 3/3
Hot-Liquid Heat Retention at 4 Hours: 3/3

Total: 12/12

 

Engel 30-ounce Tumbler

Thermal Cups

Bill Doster

Engel 30-ounce Tumbler
$40

This is the magnum cold-cup size and intended to keep you refreshed from dawn at the ramp to afternoon at the fish-cleaning table. Its lid is standard, and, instead of pressing on, it screws on tightly, closing the silicone gasket positively. I’ve dropped mine a couple of times, and the lid has remained in place. Engel doesn’t specify what stainless steel it uses, but the material has no ill effects after a month at sea and leaves no metallic taste.

Extra point: The standard lid boasts a closing tab that keeps your drink sealed tight, even if it’s upside down.

Initial Ice: 15.2 oz.
Ice Lost at 4 Hours: 11%
Ice Lost at 8 Hours: 25%
Exterior Temp at 3 Hours: 73.9°
Hot-Liquid Heat Retention at 4 Hours: 76%

Ice Lost at 4 Hours: 3/3
Ice Lost at 8 Hours: 3/3
Ambient and Exterior Temp at 3 Hours: 3/3
Hot-Liquid Heat Retention at 4 Hours: 2/3

Total: 11/12

 

Stanley Cold Pint

Thermal Cups

Bill Doster

Stanley Cold Pint
$23

Stanley has been making thermal containers for the lunch-bucket crowd since 1913, and it’s hard to imagine how the Yeti crowd trampled them — unless it’s the cache of refilling your Stanley versus your Yeti. Regardless, the Cold Pint fits the hand well and slips easily into cup holders in the car and boat. It has a larger sipping hole, which accommodates safer slurping of hot coffee, but it also accounts for the ice melting faster.

Extra point: I’ll be darned if there isn’t a stainless-steel bottle opener in the lid.

Initial Ice: 8.5 oz.
Ice Lost at 4 Hours: 20%
Ice Lost at 8 Hours: 41%
Exterior Temp at 3 Hours: 73.4°
Hot-Liquid Heat Retention at 4 Hours: 76%

Ice Lost at 4 Hours: 2/3
Ice Lost at 8 Hours: 2/3
Ambient and Exterior Temp at 3 Hours: 2/3
Hot-Liquid Heat Retention at 4 Hours: 2/3

Total: 8/12

 

Stanley Adventure Packable Locking Mug

Thermal Cups

Bill Doster

Stanley Adventure Packable Locking Mug
$20

We had high hopes for this one, but they were dashed early in the test as the cup began to sweat. Never let them see you sweat. It is a handy size and shape for easy gripping or for slipping into cup holders. A stainless-steel D-ring fastens it to a tackle bag or pack. In the mug’s defense, it’s only advertised to hold its temp for 90 minutes.

Extra point: The lid closes and locks with a slide, making it possible to throw a full container in a bag without fear of it leaking.

Initial Ice: 8.3 oz.
Ice Lost at 4 Hours: 60%
Ice Lost at 8 Hours: 96%
Exterior Temp at 3 Hours: 65.4°
Hot-Liquid Heat Retention at 4 Hours: 70%

Ice Lost at 4 Hours: 1/3
Ice Lost at 8 Hours: 1/3
Ambient and Exterior Temp at 3 Hours: 2/3
Hot-Liquid Heat Retention at 4 Hours: 1/3

Total: 5/12

 

Thermos Hydration Bottle

Thermal Cups

Bill Doster

Thermos Hydration Bottle
$24

Advertised to keep its cool for 12 hours, we’d say it truly lived up to expectations, retaining ice at a high level. It’s dishwasher-safe with a BPA-free, push-button pop-up lid. The water bottle can be used for anything, including as a travel flask in check-on baggage. It’s a little too narrow to fit snuggly in a boat cup holder but fits well in an automobile. It’s leak-free, so you could throw it in the bottom of a bag.

Extra point: It pops open like a switchblade and snaps firmly shut with a resounding click.

Initial Ice: 9.8 oz.
Ice Lost at 4 Hours: 3%
Ice Lost at 8 Hours: 14%
Exterior Temp at 3 Hours: 71.2°
Hot-Liquid Heat Retention at 4 Hours: 83%

Ice Lost at 4 Hours: 3/3
Ice Lost at 8 Hours: 3/3
Ambient and Exterior Temp at 3 Hours: 3/3
Hot-Liquid Heat Retention at 4 Hours: 3/3

Total: 12/12

 

Tervis 16-ounce Tumbler

Thermal Cups

Bill Doster

Tervis 16-ounce Tumbler
$17

The cool factor from Tervis is high, but the cold factor was lacking in our test. It didn’t sweat as quickly as the Stanley Adventure packable locking mug, but it was right behind it and lost its ice just as quickly. Its double-walled construction is sturdy but not as sturdy as steel, and it doesn’t lend itself to vacuum insulation like steel. Still, it will remain the glassware of choice among boaters.

Extra point: The pirate emblem inside was neat, and it comes with many nice options — like a closable lid.

Initial Ice: 7 oz.
Ice Lost at 4 Hours: 76%
Ice Lost at 8 Hours: 100%
Exterior Temp at 3 Hours: 57.2°
Hot-Liquid Heat Retention at 4 Hours: 67%

Ice Lost at 4 Hours: 1/3
Ice Lost at 8 Hours: 1/3
Ambient and Exterior Temp at 3 Hours: 1/3
Hot-Liquid Heat Retention at 4 Hours: 1/3

Total: 4/12

 

How We Tested
We acquired a variety of cups the old-fashioned way: We bought them at Bass Pro Shops, West Marine and a MarineMax dealer — the only dealer in Orlando, Florida, with a supply of the popular 20-ounce Yeti Rambler. All but one came with a lid — the Yeti 10-ounce Lowball. To keep things fair, we purchased an optional lid for it.

At 2 p.m. on a 75-degree day, we set our cups in the shade of a hardtop and filled each with ice, shaking the ice down until we barely closed the lids. Then we weighed the ice each contained and replaced it. Four hours later, we drained the melted water and weighed the remaining ice. We repeated the process again at eight hours. The dimensions of each container impacted ice capacity, even among containers of the same liquid capacity, so we decided to calculate and score on the percentage of remaining ice at each time of measurement.

Since these containers were also intended to keep hot things hot, we next filled them with 120-degree water from the tap. At four hours, we measured their temperatures and noted the percentage of temperature lost. We didn’t measure at eight hours because anybody who can’t drink coffee in four hours shouldn’t be bothering with it.

How We Scored
We calculated the average percentage of ice lost at each measurement point and then awarded points as follows:
Less than 15 percent lost ice at 4 hours = 3
Less than 25 percent lost ice at 8 hours = 3
Less than average lost ice at 4 hours (29 percent) and at 8 hours (50 percent) = 2
More than average lost ice at 4 hours (29 percent) and at 8 hours (50 percent) = 1

For the hot-drink test, we established an average score and awarded points as follows:
Retained more than 80 percent of heat = 3
Retained above-average (75 percent-plus) heat = 2
Retained average-or-below heat = 1

The exterior of a thermal container should remain at the ambient temperature and not transmit the temperature of its contents, so we awarded points based on how close the exterior temp was to the ambient temperature after three hours.

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