You’ve picked out your favourite origin from your favourite roaster, bought your coffee, and brewed it to perfection. It might seem like there’s nothing left to do but pour it into a cup and enjoy.

However, choosing the right vessel – and the right material – is more important than you might think. To enjoy your cup to its fullest, you should make sure that the material you pick doesn’t have an undesirable effect on the flavour of the coffee. 

To find out how some of the most common materials can affect how your coffee tastes, I spoke to Silvio Chang, a certified Q grader and the co-founder of Unseen Select Co. 

Lee este artículo en español Cómo Los Diferentes Materiales Afectan el Sabor de tu Café

Why Material Matters

Most takeaway coffees are served in disposable cups. In the UK alone, 2.5 billion of them are used every single year. Manufacturing them uses an estimated 1.5 billion litres of water. While many of these cups are recyclable, only 1 in every 400 ends up being recycled correctly. 

Consumers around the world are more aware than ever before of the impact their purchases have on the environment. As a result, many people are switching to reusable options. But which material is best?

While preferences will vary, there are a few key things that make a material good for drinking coffee. Ideally, it should be lightweight, long-lasting, and retain heat well. It’s also important that it doesn’t affect the flavour of your coffee, by trapping lingering flavours in the material itself or by creating its own distinct, undesirable taste.

We compared four of the main materials used to make coffee cups – glass, stainless steel, reinforced plastic, and ceramics – to see how each one affects the flavour of a cup of coffee.

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Glass

Few materials are as visually appealing as glass. It’s sleek and attractive, and you can enjoy looking at your drink while you consume it. 

If your cup is made from tempered, heat-resistant glass, it will not shatter or break, no matter how hot your coffee is. If you choose a double-walled glass cup, it will also be comfortable enough to carry by hand everywhere. Glass is also generally very easy to recycle.

Silvio says that while glass cups don’t affect the flavour of coffee, “they don’t retain heat as well as ceramic cups”. As the temperature of coffee affects its flavour, it is good to make sure your coffee stays hot, but not scalding, while you drink it. 

Research shows that flavours and aromas become harder to detect below 50°C, meaning that you want to keep your coffee above this threshold for as long as possible.

Tempered glass cups and mugs are also often more expensive than ceramic, plastic, or steel cups. And while glass mugs look excellent in the kitchen or at a coffee shop, it is a less suitable material for people who want to take coffee with them on the go.

Stainless Steel

Stainless steel is virtually indestructible. Unlike glass, it retains heat well, as metal is a natural conductor of heat. It is also relatively easy to clean.

While it can be visually appealing, grease and fingerprints will show up on stainless steel very easily.

Stainless steel also has a strong metallic flavour that can affect the taste of your coffee, as well as other drinks. Although this won’t wash away, it can fade over time and use. 

Silvio notes that while stainless steel is generally very resilient, it becomes porous over time. This means that it will absorb residual oils from the coffee you drink from it, causing it to take on certain flavours and odours over time.

He adds: “The acidity in coffee can cause stainless steel to break down over time and release microscopic particles of potentially toxic substances, such as nickel.” While this isn’t likely to cause a major health issue for most people, Silvio still recommends that people only use stainless steel cups and bottles for water, rather than coffee. 

Plastic

As it’s cheap and easy to manufacture, reinforced heat-resistant plastic is often used to create coffee cups, bottles, and mugs. While plastic isn’t as strong as stainless steel, it will work just fine for hot coffee. 

However, plastic cups are often less durable than cups made from other materials, like stainless steel.

As well as this, plastic can also trap unpleasant odours and flavours over time, which will affect how your coffee tastes. Silvio says: “While you might not notice it the first time, eventually, you will be able to tell that your coffee tastes different.”

Finally, plastic is also notoriously bad for the environment, and it can be difficult to recycle in some regions. Even if you buy a plastic cup and reuse it multiple times, it may well end up going to landfill.

Ceramic

Ceramic drinking vessels are very popular, as they are inexpensive, lightweight, and retain heat well. They also have no impact on the flavour of the liquid within, which makes them ideal for coffee. 

Ceramic cups are also generally leakproof and hold their colour and design well. Silvio says “ceramic is still the best option when it comes to coffee”, as it possesses all the positive qualities of other materials, with none of the drawbacks. 

“It’s environmentally friendly, but it is the same as stainless steel which also is non-porous and heat tolerant.” The various qualities of ceramic drinking vessels led Silvio to introduce the WOKY bottle to a wider market.

Silvio says that with the WOKY, “you get the best flavour of your coffee, you’re able to carry it around, and it stays hot”. As it’s all-ceramic, it doesn’t affect the flavour of your coffee, and is safe for dishwasher and manual cleaning. 

“The WOKY bottle is the first on the market that’s fully ceramic; it isn’t just a ceramic lining. A lot of bottles use a ceramic coating which peels off or uses stainless steel as part of the mouthpiece,” Silvio tells me. He adds that because the bottle is fully ceramic, it can also be used and reused for juice, milk, tea, or even carbonated drinks.

“We see there are a lot of stainless steel thermos bottles on the market, and many people use it for their coffee. But you also hear a lot of people complaining about a ‘weird metal taste’ and how hard it is to clean after. 

“With WOKY, we’ve combined your favorite coffee mug and your travel thermos flask altogether.”

To enjoy your coffee to its fullest, you need the right tools. This covers everything – from brewing all the way through to drinking the final product.

There are a whole range of materials out there to choose from. While some might be more visually appealing or retain heat better than others, your priority should be choosing a sustainable option that keeps your coffee warm and tasting the best it possibly can.

Enjoyed this? Then read French Press to Pour Over: How to Make Great Coffee at Home

Please note: Unseen Select Co. is a sponsor of Perfect Daily Grind.

Perfect Daily Grind

Photo credits: Unseen Select Co., Jack Redgate

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