Can stainless steel ice cubes be used in coffee? Which cools better: stainless steel ice pellets or homemade ice cubes?

Recently, while FrontStreet Coffee was discussing iced pour-over coffee with friends, they discovered that most coffee shops use conventional ice cubes for cooling. By the time you reach the last few sips, the iced coffee has often reached room temperature, and the taste lacks the richness it had initially, sometimes even acquiring a watery quality. This prompted a question to FrontStreet Coffee: Why don't you use stainless steel ice cubes?

What Are Stainless Steel Ice Cubes?

Stainless steel ice cubes, also known as stainless steel ice stones, typically have an outer layer made of 304 or 316 stainless steel. They're not hollow inside but contain a colorless, odorless liquid. When shaken at room temperature, you can hear the liquid sloshing inside. There are two main types available on the market: one containing a mixture of water and alcohol, and another containing a mixture of water and glycerin.

From a structural perspective alone, stainless steel ice cubes indeed offer several advantages compared to traditional edible ice cubes. First, they don't melt as the liquid warms up, so they can remain in the glass throughout consumption. As long as the stainless steel ice cubes are cooler than the liquid, they can continuously provide a cooling effect to the beverage.

Additionally, these non-melting ice stones are relatively time-saving and convenient to use. Traditional edible ice cubes require 4-6 hours to freeze in molds, while stainless steel ice cubes only need about an hour in the freezer compartment before they're ready to use. After use, they can be cleaned and placed directly back in the freezer for storage, ready for the next time.

However, since they're called "ice cubes," naturally, what matters most is their cooling effectiveness and practicality. To address this question from a friend, FrontStreet Coffee specifically purchased four stainless steel ice stones. Next, let's conduct a comparison from multiple perspectives to see whether this legendary cooling tool is truly effective in the world of coffee.

Comparison of Volume, Weight, and Cooling Speed

Through comparison, FrontStreet Coffee's shop typically uses larger edible ice cubes for daily service—small cubes measuring 2.5 centimeters wide, with each piece weighing approximately 30 grams. Stainless steel ice cubes appear more compact, shaped as dice measuring 1.5 centimeters wide, with each piece weighing similarly to our homemade ice cubes at around 29.7 grams.

Following the merchant's recommendation (one stainless steel ice cube for optimal cooling of 50ml of beverage), FrontStreet Coffee prepared two identical glasses, each containing 100ml of drinking water. At room temperature, the water temperature was measured at 27°C. Then, one homemade ice cube was added to the first glass and two stainless steel ice cubes to the second, while observing and measuring the cooling effects of both.

Within the first two minutes of adding the ice, both glasses showed an immediate cooling trend, but the homemade ice cube cooled significantly faster. At 2 minutes and 30 seconds, the temperature in the homemade ice group dropped to 12°C, while the stainless steel group only reached 19°C. Due to the high density of the metal ice, it sank directly to the bottom of the glass, causing the water below to cool first while the surface water remained uncooled. After five minutes, the edible ice cube had almost completely absorbed heat and melted, with the water temperature dropping to 8.1°C. The stainless steel ice group maintained the same liquid volume but the temperature remained at 16°C.

When FrontStreet Coffee replaced the drinking water with room-temperature cola and milk, although the cooling effects varied slightly, stainless steel ice cubes were far inferior to homemade ice cubes in cooling speed.

Thus, while these metal ice cubes offer the advantage of not melting into water, their mediocre cooling performance makes them difficult to apply in the cooling stage of coffee extraction. After all, our iced pour-over has another name: "rapid-cooling pour-over." So, would they be effective in maintaining the low temperature of already brewed iced coffee?

Trying an Iced Pour-over

Considering the limited number of stainless steel ice cubes available and their relatively slow cooling speed, FrontStreet Coffee made a small adjustment to the original iced brewing method to achieve better chilling effects and flavor profiles. Two transparent ice cubes were replaced with four stainless steel ice cubes.

This approach serves two purposes: first, to reduce the watery taste caused by excessive ice melting, and second, to help the coffee achieve cooling effects quickly while maintaining an appropriate flavor concentration.

Coffee beans: Sidamo · Guji 8.0
Dose: 16g
Coffee-to-water ratio: 1:10 (160g hot water)
Ice: 180g (2 homemade ice cubes + 4 stainless steel ice cubes)
Grind size: Ek43s setting 9.5
Water temperature: 92°C
Dripper: V60
Pouring technique: Three-stage method

For comparison, FrontStreet Coffee also prepared a regular iced pour-over (using 120g of ice cubes, or 4 pieces) with the same parameters to brew the same coffee beans. Finally, both pots of coffee were poured into pre-chilled glasses.

In terms of taste, the mixed ice group's pour-over coffee had a drinking temperature of 18.9°C. It wasn't ice-cold upon entry but rather pleasantly cool, with aromas of raisins, sweet oranges, and black tea. The texture was smooth and maintained for about 17 minutes before beginning to warm up.

The second pot, using only homemade ice cubes for cooling, saw the coffee liquid rapidly drop to an ice-cold 6.9°C almost instantly after gentle stirring, with aromas of citrus, blueberries, and cranberries, and a clearer fruit acidity. As the ice completely melted into water, the coffee began to gradually warm up after 11 minutes, with the flavors slightly diminishing.

Taking all factors into consideration, as a new type of reusable ice, stainless steel ice cubes struggle to replace traditional edible ice in terms of cooling effectiveness, taste contribution, practicality, and even safety (they can easily crack glassware). When these requirements are applied to coffee brewing, the role of ice becomes immediately apparent. FrontStreet Coffee speculates that this might be why few coffee shops use stainless steel ice cubes in their offerings.

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FrontStreet Coffee
No. 10 Bao'an Qianjie, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473