Whether it's light or dark, clear or hazy, bitingly resinous or decadently roasty, crisp and refreshing or super juicy, all beer has one thing in common: hops.

But that's about it as far as similarities go. While every beer uses hops – even those you wouldn't immediately describe as 'hoppy' in flavour – most beers use them in a slightly different way, and often to dramatically different effects.

So what are hops? Well, in scientific terms, hops are the flowers, or seed cones, of the hop plant, part of the hemp family and in fact quite closely related to the cannabis plant. In terms of beer, generally speaking, hops are an ingredient used by brewers to achieve two things: firstly to add bitterness and secondly to add aroma.

Bitterness can be extracted from hops by boiling them to make use of compounds called alpha acids, and some hops are better than others at doing that. The alpha acids from these hops are what makes bitter bitter or adds that little bit of resinous crispness to your favourite pale or lager. Brewers call these hops bittering hops, 'hot-side' hops or hops used 'in the boil', in case you ever see that on a can, label or online description.

Aroma, meanwhile, is where you get your blockbuster hops – the hops some modern beers are named after like citra, mosaic or sabro. Hop aroma accounts for those big notes of citrus or stone fruit in an IPA and the lovely earthy herbaceousness in a pint of bitter, and it's imparted on beer after a brewer stops boiling it, either immediately at 'flame out' (when they turn off the heat) or at some stage in the following days and weeks when the beer is in a tank, fermenting. These hops are called aroma hops or dry hops, and brewers often refer to them as 'cold-side' hops. Often a brewery might list aroma hops on the can or bottle, so look out for words like citra, galaxy or nelson sauvin on the label.

When you start combining the qualities from different hop varieties all around the world, it really gets interesting

Got it? Good. Because those are the basics, but the wild world of flavour comes in when you start combining the different bittering and aroma qualities from different hop varieties all around the world. That's when it really gets interesting.

Just like with wine grapes, hops grow differently depending on the soil and local climate, which means you can get massive regional differences in aroma and bitterness: for example, growing conditions in the Pacific Northwest and West Coast of the USA are great for producing hops with high alpha acids and bold, fruity aromas. For that reason, you'll see a ton of these hops in 'American style' pales and IPAs – many of which are in fact brewed in the UK. Hops grown in Britain, meanwhile, see a lot less sun and so are typically much more earthy and herbal (hence the UK's historic and enduring love of bitters, milds and brown ales). Germany, Slovenia, France, Australia and New Zealand all have their own particular quirks again, and that influences the beers that come from those places, both traditionally and today.

So to recap, beers can be a whole lot more than just 'hoppy' (although it's totally fine if that's as far as you want to go with it, and leave the whole beer nerd thing to us). They're a delicate balance of bitterness and aroma, achieved through boiling, fermentation and the careful selection and blending of varieties from all over the world. Now here's what to expect from some of the most famous ones...

Common beer hops explained

Cascade

If you’re partial to a pale, you’ve probably got cascade hops to thank, because without this hop the whole beer landscape might look a little different. Originally bred at Oregon University (and named after the rippling Cascade mountain range that runs through the state), cascade hops were first used commercially by San Francisco’s Anchor Brewing Company in a single-hopped beer called Liberty Ale. Pale, a touch floral and slightly citrusy thanks to its use of cascade hops, it’s still knocking around today as the wizened old archetype of the American pale ale – all grapefruit aroma and lightly bitter resin that strips the palate ahead of the next sip. Liberty Ale, alongside Sierra Nevada’s now potentially even more famous pale – propelled cascade hops into bars and homes the world over, not just kick-starting the 'craft beer revolution', but also the search for ever more bodacious hop varieties to use in beer, too.

Citra

Beer has changed a lot in the last decade or so, and a good deal of that is thanks to citra hops. Originally bred in Washington State in the early 1990s and first released commercially in 2007, its pungent citrus-like qualities soon showed brewers and drinkers just how much flavour and aroma you can pack into beer, contributing hugely to the popularity of pales and IPAs. Early innovators sought to balance the hop’s bittering qualities when boiled, using the bold citrus aromas it produces when added to beer as it ferments. In recent years citra has come to be known for the latter: those fruity notes of grapefruit, mango and lychee going a long way to making the New England IPA (often just ‘Hazy IPA’) the dominant style from the late 2010s onwards.

Fuggles

Ever had a pint of Landlord? Tribute? Harvey’s Best? If so, you’ve tried fuggles – a hop that, alongside another variety called goldings, has a 150-year relationship with British beer and pub culture. Bitters, English-style pales and porters all lean on the earthy, floral and herbaceous notes fuggles offers as an aroma hop: it cuts through sweetness and provides subtlety, nuance and refreshment.

Fuggles hops from Hukins Hop Farm in Sussex

It’s not big or bold like a lot of hops from the US, and maybe that makes it less cool, but while hops like citra, cascade and mosaic sparked a revolution, fuggles gave us a beer culture in the first place. And true to form, if you leave anything long enough it’ll come back in style, so expect to see it more and more.

Goldings

Hailing from the hop farms of the Garden of England, goldings (also known as East Kent goldings, or EKG) are about as British as they come. Grown in the UK for almost 200 years, they’ve long been the backbone of British beer styles like bitters, blondes, porters and milds, and that’s where you’ll mainly still find them today. For decades, these humble hops have been celebrated for the notes of honey and clean, aromatic, herbal bitterness they give to pale beers and the nice edge of fruitiness they impart on darker beers like stouts, dark milds and porters. And thankfully, owing to an increased commitment to British hops by some of the modern breweries below, goldings are coming (somewhat) back into style.

Nelson sauvin

Hops are like wine grapes: they’re complex, they create unique combinations when blended and sometimes, they taste a bit like wine grapes, too. Nelson sauvin does all of that: a New Zealand hop that’s revered for its versatility and bold flavour profile (particularly used as an aroma hop in pales and IPAs), it tastes a little bit like sauvignon blanc – hence the ‘sauvin’ in its name. As such, in beers that use nelson for aroma, you can expect notes of white grape, as well as gooseberry and peach, just like NZ sauvignons. Used in the boil, it can give beers a nice earthy bitterness, too, and that’s why it’s favoured in some pilsners. Look out for an NZ pils on a bottle shop shelf or taplist and you’ll likely be drinking something with nelson sauvin in it.

Noble hops

All is not equal in the world of hops, or at least that’s what was thought of a specific selection of varieties grown in Central Europe back in the mid-1800s. Superior in aroma and worthy of the highest prices at market, the hops from Spalt, Tettnang and Hallertau in southern Germany – alongside saaz hops grown in the Czech town of Zatec – were viewed as ‘noble’, and as such form the backbone of many much-loved beers we drink today, not least lagers hailing from Germany and the Czech Republic. These hops give you complexity, clean bitterness and herbal aromas, often with gentle notes of spice.

Strata

Owing to space, amazing growing conditions and continual R&D, new hops emerge from the fertile farms of the Pacific Northwest on an annual basis. While some of these varieties become household names like citra and mosaic, others take seemingly forever to lose experimental scientific names, or simply never make it to market at all. Thankfully, strata did – once known by the snappy title of X331, it’s on a surefire course to becoming one of the big hitters. Such is its capacity to imbue pale ales and IPAs with bold, juicy fruit and a touch of cannabis-like dankness that it’s made it something of a darling in the beer world in the last couple of years. Expect to find it in hazy New England-style pales and IPAs with big juicy flavour and pillowy mouthfeel.