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It's the least interesting purchase in the whole set-up and the one most likely to go wrong. Filter papers come in sizes that aren't obviously numbered, half the packs on the shelf are for a different shape of basket, and nobody reads the manual for something that costs seven pounds.
Wilfa's 1.25-litre filter coffee makers — the Zense, Zense Alux, Performance Compact, Performance Thermo, Svart Performance, Classic+ and Precision — take size 4 filter papers, also written as 1x4. That's the size Wilfa UK stocks. If your machine brews around 10 cups, size 4 is what you want.
The numbers are a capacity system, not a measurement. They were set by Melitta decades ago and the whole industry followed, which is why a "size 4" from one brand fits a "1x4" basket from another.
| Size | Also written | Brews roughly |
|---|---|---|
| Size 1 | 1x1 | 1 cup — single-serve cones |
| Size 2 | 1x2 | 2–6 cups — small machines and hand drippers |
| Size 4 | 1x4 | 8–12 cups — most full-size filter machines, including Wilfa's |
| Size 6 | 1x6 | 10–14 cups — large-capacity machines |
Wilfa's filter machines hold 1.25 litres and brew around ten cups, which puts them squarely in size 4 territory.
If you want to be certain rather than probable, there are three ways, in order of effort:
That last point catches people out more than the sizing does. Cone and basket papers are not interchangeable, and a basket paper forced into a cone holder will collapse and let grounds through.
You'll see white papers and brown ones, often at the same price, and the brown ones look like the more responsible choice.
White papers are oxygen-bleached rather than chlorine-bleached, and brown papers are simply unbleached. The practical difference is taste: unbleached papers carry a more noticeable papery character into the first part of the brew. Both are compostable.
Which is why the next section matters more than the colour.
This is Wilfa's own first piece of advice for better-tasting coffee, and almost nobody does it.
Put the paper in the holder, pour hot water through it, and pour that water away before you add the coffee. It takes fifteen seconds and it does two things: it washes the papery taste out of the filter, and it warms the filter holder so the first water through doesn't lose heat to cold plastic.
If you've ever noticed that the first cup from a pot tastes slightly different to the last, this is part of the reason.
One related habit worth breaking while you're here: don't refill the water tank using the coffee carafe. It puts coffee oils into the clean water side of the machine. Use a jug, or fill the tank directly.
A 100-pack of Filtropa size 4 papers is £6.99, which is seven pence a brew.
Brewing once a day, that's a little over three months — which happens to line up neatly with how often you should be descaling the machine. Ordering both together is a reasonable way to remember to do the descale at all.
Store them somewhere dry and flat. Papers that have absorbed kitchen humidity tear when you open them out, and papers stored near anything strongly scented will carry that scent into the cup — filter paper is absorbent by design.
Yes, for these machines. Some pour-over set-ups use metal mesh or cloth filters, and each changes the cup: metal lets more oils and fine particles through for a heavier body, cloth sits somewhere in between.
Paper gives the cleanest cup of the three, and it's what Wilfa's filter holders are designed around. It also traps cafestol, a compound in coffee oils that unfiltered brewing methods leave in.
The other reason is simply practical: a paper lifts out with the grounds in it and goes straight into the food waste. A metal filter needs rinsing and periodic deep cleaning, and coffee oils will eventually build up on it — which brings its own off-flavours if you don't stay on top of it.
What size filter papers does a Wilfa coffee maker take?
Size 4, also written as 1x4. This covers Wilfa's 1.25-litre filter machines including the Zense, Zense Alux, Performance Compact, Performance Thermo, Svart Performance, Classic+ and Precision. If you're unsure, your machine's manual lists the filter size and is free to download from the Wilfa product manuals page.
Are size 4 and 1x4 filter papers the same thing?
Yes. They're two ways of writing the same size, and papers labelled either way will fit the same holder. The numbering is an industry-wide capacity system rather than a measurement.
Should I use bleached or unbleached filter papers?
Either works. White papers are oxygen-bleached, not chlorine-bleached, and both types are compostable. Unbleached papers tend to carry more of a papery taste into the brew, which rinsing the paper with hot water before brewing largely removes in both cases.
Do I need to rinse the filter paper before brewing?
It's worth it. Pouring hot water through the paper and discarding it before adding coffee removes the papery taste and pre-warms the filter holder. It's Wilfa's own first recommendation for getting the best flavour from the machine.
Can I use a reusable metal filter in a Wilfa coffee maker?
Wilfa's filter holders are designed around cone-shaped paper filters, which give the cleanest cup and lift out with the grounds. A metal filter changes the character of the coffee, letting more oils and fine particles through, and needs regular deep cleaning to stop coffee oils building up.
Running out of filter papers is the most avoidable way to not have coffee in the morning.
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