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Strength in Coffee

Black as hell, strong as death, sweet as love. It’s a phrase that has been mangled and misattributed I’m sure more times than I care to remember and whilst pithy, does any of that really make any sense to the drink itself?

Sweetness we will save for another time. Whether this refers to the addition of sugar, as in something like an Ibrik-made drink (tying it in to falsely being told as a Turkish proverb), or the perception of sweetness, as undergoing research even at this very moment it is open to interpretation.

I’m fairly confident we can all agree on what black coffee is, but what about strength? This is a much harder thing to pin down, and depending on who you talk to will be either concentration, caffeine level, roast degree or even acidity/bitterness.


A great trick used by high caffeine brands is to change your brewing instructions. Skipping the caffeine content part, we’ll get on to that, this really looks at TDS, or total dissolved solids. Overdosing the coffee will give you an immediate impact and leave you with strong coffee.

Caffeine level

This one is a bit trickier, as exemplified by the recent articles in the press, or a video by the Hoff. Varietals do vary in caffeine levels, and this is before you change species moving to Canephora (robusta). Liberica sometimes pops up but actually has less caffeine than both Arabica and Canephora, not more. Racemosa falls into the low caffeine category too. But what about roast, does dark roast really equal more caffeine?

Yes and no, or more appropriately, no and yes. Caffeine is not created in roasting, and is generally accepted as not being burnt off too (despite some still claiming that light roasts have more due to this), but what does happen is moisture loss. The darker you roast, the lighter the weight of the bean. So while the amount of caffeine in the bean is relatively unchanged, the number of beans you use for a given weight increases. So if you recommend 30g coffee for a 500ml brew (it’s early, I need coffee), then a dark roast will use more beans than a light roast, because they weigh less per bean. More beans = more caffeine.

Roast degree

To some, the taste of roast will communicate strength. On a scale of raw to burnt, then it makes sense that the closer to burnt you get the more roasted a coffee is. More = more and so more roasted is easy to align with stronger. Sometimes, you can cheat a little on colour by closing the outlet air and keeping the drum smokey for a bit to impart smokier flavours. Dark roasters will also know that bean choice can have a surprising effect on the impact of that too. Ultimately, the darker the colour reading (if you use one) the stronger a coffee is.


This perhaps is the least obvious, but one that is out on the high street for sure. Coffees that have unusual levels of acidity, (normally citric and malic in my experience) or particularly those that are not brewed quite so well, can lead to a sharp acidity and often lingering bitterness in the mouth. This is unpleasant and to some, equates to the fact that the coffee must be too strong. Ironically, sharp acidity can often be caused by underroasting, with the acetic build-up around the first crack. This is the complete opposite from using roast as an indicator!

So how on earth do you know what to put yourself, or what others scores relate to? Really, the best way is to find what works best for you and maintain your logic. You can’t ignore others that you are up against, of course, but as long as your range relates and is true, you will likely be fine.