Looking for a quick guide to size filter baskets?

You might have come away from our classes learning that the linchpin to fantastic espresso starts with defining a dose of ground coffee to use in your filter basket regardless of whether you are at home or in the cafe.

The problem with basket sizes is that they come in different styles, different diameters and different depths.

Ridged? Ridgeless? Single? Double? Triple?

What’s the deal and what does all of this mean for your humble caffe latte?

Firstly, let’s break down all the naming conventions.

Ridged vs ridgeless filter baskets

A ridged basket is easy to identify; it is typified by an indentation that runs around the entire circumference of the filter basket near the top, whilst a ridgeless basket is devoid of such an indentation.

The ridge serves the purpose of keeping the basket firmly seated inside the portafilter when knocking out extracted pucks. The filter basket is held in place by a metal spring.

Ridged vs Ridgeless filter baskets
L-R: Ridged filter basket, ridgeless filter basket.

A ridgeless basket always has the potential of being accidentally knocked out of the portafilter. In practice, this rarely happens if you knock the portafilter dead centre on the bar of the knock box/tube and come to a dead stop.

Despite this drawback, they ridgeless baskets have the benefit of knocking out pucks out a lot cleaner than their ridged counterparts. Ridged baskets have a tendency to accumulate old coffee grinds in the ridge area even after knocking out pucks.

Your choice of whether you use ridged or ridgeless filter baskets has no impact on the quality of your espresso. They serve the same purpose as both have styles pros and cons.

Single vs double vs triple filter baskets

This naming convention basically refers to how many shots of espresso you can make; generally, one or two.

Simply put; the bigger the basket, the more espresso you can make.

A single basket will easily accept between 7-12 grams of ground coffee and is used to make one espresso. The basket has a funnel shape and this is paired usually with a single spouted portafilter.

single filter basket
Single filter baskets are identifiable from their unique funnel shape

A double basket will generally be sized between 14 grams and 21 grams. The double basket usually has straight walls or walls that slightly taper in.

Straight wall vs tapered wall filter basket
Straight wall vs tapered wall filter basket

A triple basket is the name given to a basket that can accept more than 21 grams of coffee. Other than this, there is no real distinction between a double basket and a triple basket as they are still used to make double espressos.

Triple filter baskets may not fit in your regular portafilter as they are deeper than your regular double filter basket. You’ll need a deeper portafilter to accommodate triple baskets or get yourself a naked portafilter.

Pressurised dual wall filter baskets

The term dual wall refers to a basket with a false bottom. The wall you see from the top is not the same wall you see from the bottom.

dual wall filter basket

Dual wall filter baskets are only used in domestic espresso machines to help people who are using pre-ground coffee (not good!) to achieve a fake crema by pressurising the already extracted coffee through a secondary false wall with a tiny pinhole at the bottom.

Dual wall filter baskets are easy to identify and should be thrown in the trash! Invest in a proper burr grinder for home and grind your coffee fresh as needed and use regular (single walled) baskets, you’ll thank me later!

Filter basket diameters

So now that you’ve gotten your head around the fact that baskets come in ridged and ridgeless versions in a lot of different capacities, you will find that filters baskets also come in different diameters.

The most common basket diameter is 58 mm and is usually the standard size used in commercial and higher-end domestic/prosumer espresso machines. Very occasionally you will encounter 53 mm diameter baskets, and rarer again, the 57 mm basket.

58 mm – the most common size used by most brands

57 mm – incredibly rare size used by domestic machines brands like Lelit and Ascaso

53 mm – not as common but used by brands such as La Spaziale, Dalla Corte, some lever-piston machines, and some domestic machines

Some manufacturers of precision filter baskets, like the IMS E&B Lab filter baskets we use at The Espresso School, are sized ever so slightly larger than 58 mm. There are many manufacturers of precision filter baskets including IMS, VST, Pullman and others.

Precision filter baskets have one thing in common: evenly sized filtration holes. Regular filter baskets produced using regular manufacturing techniques tend to produce filter baskets with irregular sizing in diameter and even worse, partially or fully blocked filter holes.

Whip out a pair of vernier callipers and measure the internal diameter and buy an appropriately sized tamper to match. We love and use Pullman tampers at The Espresso School.

How to determine the size (capacity) of your filter basket

Oftentimes baskets often come without any information written on it, so you have to figure out what is the optimal dose for the basket you’re working with.

Here’s a quick 3 step process to determine how much coffee your basket accepts:

  1. Tare off your portafilter on an electronic scale and dose to a lightly heaped mound.
  2. Evenly distribute the grinds by gently using your index finger to sweep the grinds across the whole basket surface (without pushing down into the basket) to fill in areas where there is not enough coffee. Any excess can be scraped off.
  3. Weigh the result and repeat a few times. This should give you a pretty good idea as to whether you’re dealing with an 18 gram or a 22 gram basket.

You can safely increase or decrease your dose by 1 gram for the basket you just sized without issue.

For example, after repeating the exercise three times the scale reads 17.4 grams, 18.2 grams and 19.0 grams. You can be fairly confident you’re dealing with an 18 gram basket. This means you can dose between 17 and 19 grams in the basket without too many problems.

It’s all about ratios!

Whether you’re using a 7-gram single basket, or a 24-gram triple basket, the goal is the same; to extract the right amount of flavour from the ground coffee.

Think of ratios as a scaling recipe. Brewing espresso at the same ratio with bigger baskets, and therefore more dose will yield more espresso in your cup.

In our introductory barista course, we recommend starting at a brewing ratio of 1 to 2 and working your way up and down from there.

If you want a less intense espresso, increase the ratio, e.g. 1 to 2.2. If you want a more intense espresso, decrease the ratio, e.g. 1 to 1.8.

So let’s say we own a 14-gram double basket and are dosing 14 grams in. At a brew ratio of 1:2 your total yield should be 28 grams of liquid espresso in your cup(s). Split equally, they would produce two espressos weighing 14 grams each.

If we decide to use a bigger 20-gram double basket to make our doubles at the same ratio of 1 to 2, our total yield would now be 40 grams. Again, this 40 gram yield can be split equally into two cups and would produce two espressos weighing 20 grams each.

The difference in basket sizes and total espresso yields is clear. Brewing at the same ratio using more coffee leads to more espresso in your cup and vice versa.

How much espresso is in your cup will have a direct impact on final drink concentration when adding steamed milk.

So how strong do you want your milk drinks to be?

The difference in yield between the espressos produced by the different baskets is considerable. Both are considered double espressos, yet the difference of 6 grams in yield means that 43% more espresso is being produced simply by using the bigger basket (and dose) and brewing to the same ratio.

How much espresso in your cup has a direct impact on milk beverage strength, whether it is a caffe latte, cappuccino or flat white.

Assuming a fixed cup size, more espresso (i.e. more yield) will produce a stronger tasting drink when topped up with steamed milk. So whether you choose to use an 18 gram basket or 22 gram basket generally hinges on your cup size.

If you’re using 150 mL cups, an 18 gram dose might produce a drink with the perfect balance between the espresso and milk. However, using a 22 gram dose might produce a milk drink that is no longer harmoniously balanced.

Conversely, an 18 gram basket (and dose) paired with a larger 220 mL cup might produce an incredibly milky and weak drink.

If you’re a cafe you should choose your basket size wisely to match your cup sizes so all your milk drinks are perfectly balanced.

Phew!

Seriously, who knew filter baskets could be so complicated?! That’s probably more than you ever wanted to know about filter baskets and hopefully, I’ve demystified espresso filter baskets for you. If you have any questions, please hit us up in the comments below!

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