ROK Zero Jar 

If you’re investing in a good-quality coffee, you’re taking time over your technique or you’ve perfected your machine’s settings...whatever your journey towards the perfect cup, you don’t want it all to fall down when the coffee you picked out loses its flavour. 
For me, I’m a hoarder – when I have something I consider a ‘treat’, I want to consume it slowly, and nothing stresses me out more than balancing that instinct against knowing that foods can only be kept so long before they go off. With the ROK Zero Jar, one no longer has to worry about that with coffee.  
The reason coffee ground can lose its taste and crema over time is oxygen. Mixing with O2 affects coffee’s taste, but ROK’s Zero Jar solves this problem, without needing any elaborate set-up. No valves, no vaults – you don’t need a special room like a cigar humidor! And yet, these are no simple jars: the Zero Jar creates an air-tight seal – one that is easy to make, and, even more amazingly, easy to open. 
The key to these jars is their lids. The jars themselves are a convenient size (taking up to 250g of coffee) and an attractive design that put me in mind of a science experiment: they will look classical and neutral in your kitchen or pantry, as well as putting your coffee beautifully on display through the glass. However, the lids are where the magic happens.  
Designed from a combination of plastic and silicone, these lids press down towards your coffee with a pressure much like the lid of a cafetiere, but these come with a difference. A slit in the top of the lid has been designed to allow air to release as the stopper slides downwards, and yet does not leak it back in. This design allows the lid to not only remove air from storage when you first fill the jar, but also allows said lid to lower as your coffee levels lower, thus keeping your coffee away from air as much as possible. It’s simple yet extremely effective! The hiss is extremely satisfying,  

This creates an air-tight seal, and yet, vacuums like this make things a struggle to open again, right? That's the crazy thing about this jar lid - the o-ring releases the air tight seal that the lid makes, allowing the plunger to move without difficulty.  
It’s important to note that whilst these jars hold 250g of coffee (or any granular food that you feel like storing in there instead!), they come in pairs. So, you’re actually getting 500g of storage for the price!  
5/5  The Zero Jar without its lid, being filled up with coffee beans
Air-tight seal 
Protects from air damage 
Easy to open 
Lowers with contents level 
Beautiful glass finish 
Comes as a pair – 500g storage 
These are glass, so just be careful not to break them!