Getting Started: The Different Brewing Methods
Getting started into brewing specialty coffee can be tricky, it’s easy to end up buying equipment you don’t really need, or spending way too much for an inferior product, simply because there aren’t that many reliable resources available.
Your first step should typically be this: go out to specialty cafés and try out coffees brewed with different methods to find out which method you like the most. Try to ensure that your coffee and barista remain as consistent as possible. And if you’re feeling up to it, talk to your barista! He/she will be able to tell you about the pros and cons of each method, as well as the typical extraction profile of each method.
But if you don’t have the time (or don’t want to spend so much money at a café), here’s a rough breakdown of what you can expect from the various methods:
Presses (includes: French press, Aeropress):
A typical French press pictured with the plunger up (in the “open” position) during the steeping stage. Note: a gooseneck kettle is not necessary when making French press coffee!
The distinguishing feature of this category of brewers is that they utilise positive pressure [>1atm] caused by the action of a plunger; this gives it a characteristically bolder body in comparison to atmospheric methods, due to the greater agitation, and increased rate of reaction from the pressure. The increased agitation levels and reaction rate usually yields a characteristically bolder and more intense cup of coffee, with a tendency to push through sediments from the fines during the grinding process, yielding a “thicker” full-bodied, brew. The aeropress reduces this a little by using gentler, air pressure (remember, air is compressible, and hence regulates the pressure to a certain point), this yields a cup more similar to pourover coffees, whilst maintaining that bolder intensity of the French press.
The advantage of a pressed coffee is that you can actually “steep” the coffee through immersion, this allows you to control the extraction duration to tune the brew to your liking, since the brew duration is no longer necessarily dictated by grind size or flow rate.
Pourovers (includes: V60, Wave Dripper, Chemex, Melitta, Nel Dripper, and their respective variants):
The Torch Mountain dripper, using the Kalita Wave 155 brown paper filters, making use of the flat-bottom of the dripper. The interesting thing about this dripper is that it is able to use most types of filters due to the addition of a large central hole in the base, which allows the point of cone-shaped drippers to stick through.
The Chemex is a staple in any specialty café, from it’s iconic design (it’s even featured in MoMA, and has been awarded numerous awards), to it’s characteristic clean flavour, it is well-loved by coffee enthusiasts all over the world. The folding of the filter paper is a little event in itself, almost akin to folding a paper airplane, or origami.
The Hario Woodneck (Nel) dripper features a cloth filter, that is allowed to freely hang from a ring support, which gives the ground bed a characteristic bowl-shape, making it one of the most challenging pourover methods to brew due to it’s odd shape.
Arguably the largest and most varied category of brewers, pourovers are offer the best balance due to their adjustability and variations. Their distinguishing feature comes from their namesake, that water is poured over the grounds during the brew and flows downward into a vessel by gravity.
There are two major types of pourovers: the cone-shaped pourover, and the flat-bottomed dripper (named as such, because the flow is usually more drippy than on a cone-shaped, although usually the term dripper is now synonymous with pourover). But the differences don’t just stop there. Filter types vary from paper [most common], to cloth, and even metal filters.
This method is arguably the most demanding on the brewer, because it requires focus on the pour throughout the duration of the brew. As such, it is highly recommended that you use a gooseneck kettle for more precise control. This method is the easiest method to learn the different characters of the type of filters, as all the different filter materials are available for this method.
Since water is poured over the grounds through the filter of the dripper, the extraction is largely controlled by the way the brewers pour the water into the grounds. Pouring for too long in one spot will cause that region of the bed of grounds to extract more than other parts. This is also where the cone-shape and flat-bottoms differentiate from each other. The bed depth of the grounds means that the deeper the bed, the more grounds there are to pass through, hence the more water should be poured over that region. Hence making it critical that cone-shaped drippers are poured in a spiral pattern to prevent over-extraction of the edges, which have a shallower bed than the center.
The flow-through nature of the dripper also presents a unique challenge in that the brew duration is not as controllable to the brewer as other methods. This makes the design of the dripper, grind size used, and the pour rate critical to the extraction of the coffee.
Vacuum Pot or Syphon/Siphon:
One of the most neglected of brewers due to the lack of variation in brewer style, but what it lacks in variation, in more than makes up for in giving you a clean cup of coffee. Simple to operate, but extremely hard to master, there is a reason why a lot of baristas do not recommend this method to a customer; not because it is bad in anyway, but simply because it’s the odd, ostracised kid on the street. People who don’t take the time to learn about it’s principle will find it extremely hard to get right.
To begin, let us deconstruct the apparatus. There are three essential components to a syphon:
A “hot” vessel at the bottom, usually in the form of a bulb
A “cool” vessel on the top with an insulated tube connecting and creating a relatively airtight (just enough to allow the differential pressure to work it’s magic) seal between the hot and cold vessels
And last but not least, the filter, usually made of cloth, with a metal support structure, and a spring tensioner attached to a hook, to affix it firmly in place at the bottom of the cool vessel.
The syphon works on the principle of differential pressure, specifically using vapour pressure (it really only works as a “vacuum” [negative pressure <1atm] during the final stage of extraction). First, water, preferably pre-heated to reduce waiting time, is put into the bottom “hot” vessel, followed by the attachment of the filter to the bottom of the “cool” vessel. The top is then affixed to the bottom, and heat is applied.
What happens now is as the temperature of the water in the bottom flask increases, so does its pressure (simple physics; greater energy + same volume = greater pressure). The narrow tube between the two vessels, and the resistance of the filter creates a “partially permeable membrane”, which allows the pressure to build, yet allows the water to flow through as well (an open vessel will just vent the pressure, a closed vessel won’t allow water through). As the pressure in the bottom flask increases, the pressure in the top vessel remains atmospheric, this creates a pressure differential, which causes the water to migrate from the bottom flask to the top (to equilibrate the pressure gradient).
When the water has migrated up (it is normal for a little bit of water to remain in the bottom flask, this is due to the water level reaching the end of the glass tube, hence introducing air into the tube which releases the pressure [think drinking bird]), the coffee grounds are added, and after the evening of the surface with the supplied bamboo stick, the coffee is allowed to bloom and pre-infuse for about 30 seconds. This is followed by a few rounds of agitation with the bamboo stick close to the surface, and usually up to halfway down the fluid level, in a fore-aft motion two to three times with the bamboo stick, repeat with a 90º orientation shift. Important: Do not agitate now in a swirling motion, as this will increase the risk of over-agitation, and hence over-extraction due to the inertia of the fluid in the cylinder, which will continue in a spiral motion for a long duration. Also note that as more water migrates up, the lower your heat setting should be (as there is simply less water in the bottom flask, hence less energy required for heating)
Syphon brewing at the agitation stage, a bamboo paddle is used to agitate the grounds in the brew in a fore-aft motion, in order to prevent over-agitation from the momentum of the fluid in a swirling motion.
Nearing completion of your brew (about 2–3 minutes in), agitate the brew vessel in large swirling motion around the edge for 2–3 revolutions as you cut the heat off. This creates a vortex as the pressure gradient reverses, forming a relative vacuum (from whence the name comes from) in the bottom vessel, sucking the coffee from the extraction vessel through the cloth filter back down to the bottom flask. The swirling motion will cause the coarser grounds, which have more mass to settle first, around the center, while the finer grounds settle around the edges, causing a characteristic dome shape to form on the filter once the coffee has drained completely to the bottom flask. (Source: World Siphonist Championship [WSC])
The dome shaped “bed” of grounds just before the completion of a syphon brew.
In principle, brewing a syphon is somewhat similar to a pressed coffee, because both utilise pressure (albeit positive on a press, and negative on a syphon) during the brew, and that they both give you as the brewer the ability to control the extraction time to a certain extent. That being said, the kind of coffee brewed by a press and a syphon are essentially regarded as polar opposites, with the syphon being more subtle, clean, and nuanced; while the pressed being thicker, fuller, and more intense. This is due to the way the pressure is being used, the syphon’s pressure differential method is much gentler, and is mainly used for the migration of water up, and coffee down (with the downward stage being a bit more than just migration due to the agitation, which plays a part in extraction and distribution of the grounds).
Espresso and its variations:
Espresso coffee is characterised by its use of high pressure (typically 9 bars [900kPa or approx. 130psi]) and high temperature to increase the rate of extraction, as such, it usually takes only about half a minute to prepare a shot of espresso. This makes the coffee characteristically bold and intense, with a full body and high Total Dissolved Solids (TDS) content.
Procedures: The procedure in making espresso coffee is markedly different from other brew types because it requires the packing of the grounds into a filter basket to ensure even spacing and thus extraction of the grounds. This packing stage is known as tamping and requires the use of a specialised tool designed to fit precisely into the basket of the metal basket of the portafilter. This is similar to the levelling of the grinds in other brewing methods (known as the “distribution” of grounds, also important in espresso coffee prior to tamping).
Distribution, is also an important aspect in ensuring an even extraction during the approximate 30 second duration. This stage of the craft helps to level out grounds and also crumble down clumps of grounds that may be formed during the grinding stage. These clumps, will cause irregularity in spaces between grounds in the filter baskets and will cause air pockets to be present. This is when you will see irregular blonding during early stages of shot extraction. You may even see bubbles flowing out with your espresso through the spouts!
Unequal distribution will also lead to channeling; as the water in espresso coffee is flowing with high pressure, it is critical to ensure that the grounds are packed evenly, as any unevenness will cause the water to push through the area of least resistance, causing either a bias in extraction or pushing past the grounds almost completely with minimal extraction due to the channels formed when the water pushes past the grounds.
The espresso is expected to be extracted within 30s [+/-5s] with a volume of 30mls [+/-5mls] per spout. Moving forward with new age espresso, most of us have started measuring the grounds used and also the yield of the beverage, both of which are measured in grams. This allows barista to look at espresso as something similar to a pourover coffee, in which ratio is one of the key aspects in determining the “perfect brew”.
Being a concentrate for most beverages consumers purchase at a cafe, it also means that it is highly volatile and stales quickly. Unlike a brewed coffee, espressos are better known as a “quick fix”, and it is almost mandatory for it to be served and drunk almost immediately post-extraction. You would know that your espresso isn't fresh or badly extracted if it’s served to you with a thin crema, as it dissipates almost immediately after extraction through a drop in temperature.
This usually occurs in the same way a soda gets flat (although at a much quicker rate), in which the dissolved bubbles that reach the surface of the liquid burst due to the boundary of atmospheric pressure and liquid pressure at the surface of the liquid. This causes a build up of internal pressure, which overcomes the surface tension of the bubble, causing it to burst, as the bubbles burst, the insulating foam layer dissipates, which allows for direct contact of the coffee with the atmosphere, causing cooling and oxidation of the coffee, leading to the degradation of the shot.
The spectrum of clarity is inversely proportional to fullness body, but what is clarity and body? The fuller the body of a coffee, the richer it tastes, with all the flavours hitting you in your face almost at once. While a clearer coffee, which has less body, usually gently laps over your tastebuds, with the flavours gently overlapping and transitioning over into the various complexities as it flows down and over your palate. Imagine an espresso as BIG BOLD LETTERS while a syphon coffee is a gentle flowing handwritten script. The amount of body a coffee has refers to the intensity of the flavours, while the clarity of the coffee refers to the separation of the flavours. They are usually inversely proportional, but they are not mutually exclusive.
The spectrum of clarity and body is generally affected by a few factors, which goes something along the lines of:
High positive pressure (presses, espresso machines) — least clarity, most body
Atmospheric (pourovers) — variable clarity & body
Negative pressure (syphon) — specifically syphon coffee; most clarity, least body, although not directly related to the pressure [partly because the differential pressure allows regulation of the force exerted by gravity]
Grind size:
Fine — least clarity, most body
Medium — moderate clarity & body
Coarse — most clarity, least body
Filter material:
Metal — depends on pore size, but usually has the most body
Cloth — usually heavier on body, due to the allowance of oils to flow through
Paper — usually medium to very clear, as the paper will absorb oils, an important note is to always pre-wet a paper filter in order to wash away as much loose fibres (paper pulp) as possible that would otherwise adversely affect the taste of your coffee prior to brewing your coffee
In general, the quicker the rate of reaction (i.e. higher temperature, greater agitation, finer grind, higher pressure), or the longer you extract, the greater body your coffee will have assuming all other parameters are constant (brew ratio, brew duration, roast level, etc.)
More pictures of the various brewing methods in a later post (blog post limitations)
Note: the information herein may be updated periodically in order to ensure the most comprehensive and accurate information on the basic brewing types. Any exceptional brewing methods will be discussed in their own post (i.e. Turkish coffee, AlphaDominche Steampunk, La Colombe Dragon, etc.)
