Relentless SOUR TWIST

Posted on August 27, 2023 | Last updated January 31, 2025

This is the 2019 fall release of Relentless SOUR TWIST, from the British brand Relentless, which was originally owned by Coca-Cola and is now under Monster Energy.

As of 2023, it has already been discontinued, and it seems to only be available as store stock. Personally, this was an energy drink I rated highly both in terms of flavor and ingredients... Let’s dive into the review.

Relentless SOUR TWIST

Manufacturer	ENERGY BEVERGES
Country of Origin	UK
Price	1.19 GPB
Flavor	Apple
Total rating	★★★☆☆

Author information Author: Energy Drink-kun

In 2001, while living in the United States, I encountered energy drinks through the dance scene and was deeply impressed. After returning to Japan, I found that energy drinks were considered novelty beverages, so I established a comprehensive website in 2013 to share the true appeal of energy drinks. As an energy drink enthusiast, I began drinking them seriously again, collecting over 7,000 varieties of energy drinks from various countries. I am also active as a critic and expert, receiving media interviews.

Flavor of Relentless SOUR TWIST

Upon opening, a sweet and tangy fruity aroma of apple flesh bursts out. The color is a fluorescent green, just like the can, which is quite a surprise compared to what you'd expect. It’s a green apple flavor, but instead of the color of the apple flesh, it matches the skin’s color in a fluorescent tone, which is a fun and energy-drink-like touch.

Flavor of Relentless SOUR TWIST

When you take a sip, you get a sweet and tangy green apple flavor with a strong taste of the apple flesh’s sweet-tart richness. The flavor and aroma are incredibly well-executed, offering a high-quality green apple flavor.

The taste itself is just the right balance of sweetness and tartness, and the aroma is particularly well-crafted. The lingering fragrance after drinking allows you to enjoy the deliciousness of the green apple flavor.

What’s surprising is that I didn’t notice this at first, but Relentless, now under Monster Energy, has a half-sugar formula, which didn’t make itself obvious in the texture or overall flavor. It was a nice surprise.

It was a nice surprise. I was initially concerned about consuming too much sugar from a 500ml can, so the half-sugar formula was a pleasant discovery. The satisfaction of the sugar content is so high that it seems unnecessary for them to release full-sugar versions in the future.

Flavor of Relentless SOUR TWIST

Zero sugar is becoming the mainstream in energy drinks, but it’s great to have the half-sugar type, as it increases the options depending on situations like before or after intense exercise.

Energy Ingredients of Relentless SOUR TWIST

It contains 160mg of caffeine and 2000mg of taurine. As mentioned in the taste review, it has about half the usual sugar, with 28g of sugar and 112kcal. Unless you have an extremely active lifestyle with heavy calorie consumption, this amount of sugar and calories feels just right.

Design of Relentless SOUR TWIST

The design features the Relentless common logo on a yellow-green background.

Design of Relentless SOUR TWIST

Looking at this color and the "SOUR TWIST" label, most people will probably imagine a green apple flavor. However, I wish the design could have been more thoughtfully connected to the flavor, perhaps featuring a fruit that represents the flavor more directly.

Originally, even during Coca-Cola’s ownership, the Relentless series didn’t have designs that directly hinted at the flavor. Instead, they featured detailed, heavy, and mysterious designs that were unique for each flavor.

Since Relentless became part of Monster Energy, however, all flavors use the same design, with only the color changing to match the flavor. There are only occasional new flavors released... It’s especially disappointing considering how good the flavor was this time. I really hope for a design overhaul in the future! (^_^;)