Over the past few years we’ve seen an explosion in coffee brewing devices, along with an ever increasing range of coffee filters. In this article we take a look at the main characteristics of the various filters on the market.

Although there are many different size and style variations, coffee paper filters are made from the same raw product, paper. Typically they are made from 100g/m2 filter paper with the pulp being coarse, long fibres, usually from fast growing soft wood. The aim of the filter paper is to separate the grounds from the coffee so you end up with a clean brew. Filter papers need to be thin and porous enough to allow liquid through, while at the same time preventing any coffee particles from entering your cup.

Bleached v Unbleached

There is a lot of debate around bleached and unbleached filters. If the papers you use are white then they will have been bleached, as white is not a natural paper colour. The bleaching process sometimes utilises chlorine and sometimes uses oxygen. It is worth noting that even oxygen-bleached filters use small amount of chlorine so those with an eye on the environment might choose to look at the unbleached options. As its name implies unbleached filters do not undergo the whitening process and therefore have a natural, brown colour. On the down side there are some who believe these brown filters impart a paper-like taste on the coffee. This can easily be remedied by wetting the filter paper thoroughly before brewing the coffee.

Bleached and unbleached filter papers

As well as filtering coffee particles, paper also absorbs the oils in the coffee. This gives the resulting coffee a cleanliness and clarity which we don’t get from brew methods such as the coffee press. The oils in coffee are called diterpenes and there is evidence that too much of these can block a receptor in your intestines which regulates cholesterol. We’re probably talking 5 to 8 cups a day here to do any harm but maybe it’s a fact worth knowing!

Pointed Cones, Flat Cones and Baskets

There are two broad shapes of filter papers, cones and baskets. I n short, you need to match the shape of your filter paper to the shape of your filter basket. For example, the Hario V60 drippers use pointed, cone shaped filter papers, while the Clever Coffee Dripper uses a flat based cone. Larger, commercial coffee brewers will use very flat bottomed, basket shaped filter papers. The Sage Precision Brewer is able to accommodate both the pointed filter cones as well as the flat bottomed ones.

Some filter papers have crimped edges, particularly those used in large commercial brewers. This is to prevent the papers from sticking to the sides of the cone and inhibiting flow. V60 and Filtropa papers on the other hand are smooth but the brewers themselves have a textured design.

Size Matters

Hario 1 Cup and 2 Cup Papers – even the same brand can use different types of paper!

You need to pick the correct size of filter paper for your brewer. The size of the paper you use relates to your brewer and batch size. Hario produce 1, 2 and 3 cup filter papers (easy so far) while Chemex produce half moon and square/round papers for their 3 cup and 6 cup brewers respectively (not so easy now, is it?).

Then you have the Filtropa range of papers which are commonly used in Clever Coffee Drippers, Moccamaster brewers and Wilfa Brewers. Although the sizes range from 0 to 6, (no size 3 though?), it is the size 4 which is needed for the aforementioned brewers.

Watch that dose!

I often see people trying to stretch the capacity of their filter papers, trying to brew as much coffee as possible. Remember that coffee blooms in the basket and if your grind is too fine you risk stalling the brew and potentially (in the case of electric brewer) your coffee can rise above the level of the paper. This will definitely not produce a smooth, clean coffee!

Other materials

A range of other materials are used to produce filters. Nylon, cloth and metal are all used to produce reusable filters, though the porosity of these materials means the resulting brew will contain the oils (diterpenes) as well as some sediment, depending on the filter use. The combination of those oils and suspended particles creates the sensation of more mouthfeel.

We’ve experienced some really interesting brews using cloth filters with the V60, Chemex and Clever Coffee Dripper.

Cloth Filter for Hario 2 Cup V60

Melitta produce a range of filters which contain 40% bamboo, a self-renewing resource that grows back when cut.

Filter Coffee is More Acidic – or is it?

Filter coffee is often described as being more acidic than coffees brewed using other methods. This might not be entirely true. The process of filtering the coffee removes sediment and oils which, if present, would probably balance the acidity in the cup. Filter coffee has more perceived acidity as opposed to actual acidity.

We stock a range of the most common filter papers on the market including cloth filters for the Chemex and V60 coffee brewers.

This February we are celebrating the joys of filter brewing with our #FilterFeb Giveaway. Enter and you could be in with the chance of winning a Moccamaster Filter Brewer, a Wilfa Filter Brewer or a V60 Brewing Set.

FILTER PAPERS EXPLAINED via @carvetiicoffee

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