You order the same drink you always order, at a branch you do not normally use, and it tastes wrong. Not terrible — just different. This is extremely common and almost never a matter of different ingredients.
Batch age is the biggest factor
Brewed coffee is made in volume and held in insulated urns. It is at its best within a fairly short window after brewing, and it flattens out noticeably after that — the brightness goes first, then it turns slightly bitter and dull.
A busy branch empties an urn quickly and brews constantly, so almost every cup is fresh. A quiet branch at an off-peak hour may be pouring from something that has been standing for a while.
This single factor explains most of the variation people notice. It is also the easiest to work around: at a quiet time, it is entirely reasonable to ask when the batch was brewed. Staff answer this question all day and will usually offer to brew fresh if it has been sitting.
Water
Coffee is overwhelmingly water, and water differs by municipality. Hardness and mineral content change how the coffee extracts and how it tastes in the cup.
Most locations filter, but filters have a service life. A branch with a filter near the end of its cycle produces a different cup from one with a fresh filter, using identical beans.
Nothing you can do about this one — but it is why the same chain can taste consistently different between cities.
Grind and equipment calibration
Grinders drift. Brewers need descaling. Machines get serviced on a schedule that varies by location and by how conscientious the operator is.
A slightly coarse grind under-extracts and tastes thin and sour. Slightly fine over-extracts and tastes harsh. Both are within the range of "working normally" from the equipment's point of view, and both produce a noticeably different cup.
Who made it
Espresso drinks are more sensitive to this than brewed coffee. Milk steaming in particular is a skill — temperature, texture and how well it is integrated all vary between people, and they change how the drink tastes more than most customers realise.
A latte made with slightly overheated milk tastes flatter and slightly scalded. The same drink with properly textured milk tastes sweeter, without anything extra being added.
Turnover and storage
Beans are best used within a window after roasting. High-volume branches cycle through stock quickly. Very quiet locations may be working through a slower-moving supply.
The same applies to milk, syrups and anything else with a shelf life. None of it will be out of date — but "fresh today" and "fine for another week" do not taste identical.
If a cup is genuinely bad rather than just different, say so at the counter. It will be remade. Staff would far rather replace it than have you leave unhappy.
What you can actually control
- Ask when the batch was brewed at quiet times. The most useful question available to you.
- Order the higher-turnover item. Whatever is selling fastest is freshest — usually the standard blend rather than a less popular roast.
- Go at a busy time if freshness matters more than the queue.
- Order espresso-based if you want consistency. It is made to order, so batch age is not a factor at all.
What is not happening
A few things people suspect, which generally are not the explanation: different branches using cheaper beans (the supply chain is centrally controlled), deliberately weaker drinks to save money (portions are standardised), or one branch having a secret better recipe.
The variation is real. The cause is almost always freshness, water, calibration or technique — not the ingredients.