Coffee making in a carob machine is always a balance between science and art, where each variable plays a critical role in shaping the taste profile of the drink. Many owners of expensive equipment mistakenly believe that the quality of grain or the power of heating are the only factors of success, forgetting about the fundamental parameter - particle size. Exactly. milling determines the rate of water spill through the coffee tablet and the degree of extraction of flavor and aromatic substances.
The wrong size of the fraction can turn even an elite monosort into bitter slurry or, conversely, into an acidic watery liquid deprived of the body. Understanding the physics of the extraction process allows you not only to blindly follow the instructions, but to feel the machine and adapt the settings to the humidity, freshness of grain and a specific model. holder. In this article, we will discuss in detail what the structure of coffee powder should be to obtain a dense, viscous foam. cream and a rich taste.
Extraction physics and the role of particle size
The process of brewing espresso is based on the passage of hot water under high pressure (usually 9 bar) through a pressed coffee tablet. If the particles are too large, water will pass through them too quickly, before dissolving the necessary oils and solids, leading to the loss of water. subextraction. As a result, you will get a drink with a sharp acidity, lack of sweetness and watery texture, devoid of characteristic density.
The reverse situation occurs with excessively fine grinding: meets too high resistance, the time of contact of water with coffee increases, and unwanted bitter compounds and tannins are washed out of the grain. This is a condition called re-extractationIt is easy to identify by the bitter, astringent taste and dark, almost black color of the trickle. The middle ground This is achieved when the resistance of the coffee tablet is optimally matched to the pump pressure of your machine.
⚠️ Attention: Do not try to compensate for improper grinding by changing the force of pressing (temperov). Excessive pressure can damage the filter grid or create channels, and insufficient pressure can destroy the pill before the strait begins.
It is important to consider that different models of carob coffee machines may have different geometry of the water distribution group, which also affects the grinding requirements. For example, boiler machines and thermal block machines may react differently to a change in the density of a coffee tablet.
Visual and tactile signs of proper grinding
To determine the correct setting of the grinder can be not only by the taste of the finished drink, but also by the appearance of the coffee powder. Carob coffee machines require a thin, almost powdered grind that feels like fine salt or powder, but not dust. If you swipe on freshly ground coffee, it should be soft, but individual grains can still be felt, unlike flour, which is completely homogeneous.
When visually inspected in the holding before tempering, the coffee should lie flat without visible large fragments or "stones". The presence of heterogeneity often indicates a low quality of grinders or their wear, which leads to uneven extraction. In this case, the water will follow the path of least resistance, forming a channelAnd some of the coffee will be left unbrewed.
- 🌫️ Consistency: Resembling fine sea salt or powdered sugar, slightly sticks together when compressed, but easily crumbles.
- 🖐️ Tacticality: When rubbing between the fingers, a fine-grained structure is felt, the absence of sharp large particles.
- 📦 Conduct in the holder: After tamping, the surface of the tablet is smooth, matte, without cracks at the edges.
It is worth noting that visual assessment is subjective and requires experience, so you should rely primarily on the time of the strait. However, it is tactile control that helps to quickly diagnose problems with the millstones, such as dullness or pollution, which cannot be seen with the eye.
Before each new grind, be sure to blow the grinder millstones from the remnants of old coffee, so as not to mix the flavors and not violate the dosage.
Effects of fresh grain and humidity on settings
Freshness of roasted coffee is a dynamic parameter that directly dictates the necessary changes in the settings of the grinder. The freshly roasted grain (aged 3-7 days) contains a huge amount of carbon dioxide, which, when in contact with water, creates additional resistance. Such coffee often requires a slightly larger grind to avoid excessive pressure in the group and bitterness.
As the grain ages, usually after 3-4 weeks from the roasting date, it loses moisture and gases, becoming more brittle and dry. This coffee requires a finer grinding to create sufficient resistance to water. If you continue to brew old coffee at the settings for fresh, you will get a flat, sour and empty drink, as water will slip through the loose pill too quickly.
Humidity also plays a role, especially in the off-season. In wet weather, coffee powder can absorb moisture from the air and stick together, increasing resistance. In dry hot weather, static electricity can, on the contrary, make grinding more airy. Experienced baristas know that calibration It is a daily process, not a one-off action.
⚠️ Attention: Store coffee in sealed containers with a degassing valve. Contact with oxygen accelerates the oxidation of oils, and even proper grinding will not save the taste of rancid grains.
Table of correspondence of time of strait and taste
The most objective tool for determining the correctness of grinding is timekeeping. The time it takes for 36-40 grams of drink to flow from a double horn (dorsale) of 18-20 grams is the main indicator. The classic standard is the range from 25 to 30 seconds, but modern techniques allow for variation of this parameter depending on the desired taste profile.
| Strait time | Grinding characteristics | Taste profile | Recommended action |
|---|---|---|---|
| Less than 20 seconds. | Too big a big one. | Sour, watery, no crema. | Reduce the grinding step (make smaller) |
| 25-30 sec. | Optimal. | Balanced, sweet, dense | Leave it unchanged. |
| More than 35 seconds. | Too small. | Bitter, astringent, dark crema | Increase the grinding pitch (make it bigger) |
| Drips in drops | Extremely small. | Very bitter, burnt taste. | Increase the grinding step significantly |
It is important to start counting down time not at the moment of switching on the pump, but from the moment of the first drop of coffee on the nose of the holder. This will eliminate errors associated with the preliminary wetting of the tablet and filling the internal channels of the group. The accuracy of the timer is critical here, the difference of 2-3 seconds is already palpable in taste.
Strait time is your main diagnostic tool: if the taste doesn't like, change the grinding first, not the temperature or amount of coffee.
Uneven grinding problems and channels
One of the most common problems with carob coffee machines is the formation of channels (channeling). This phenomenon occurs when water finds the path of least resistance in a coffee tablet and punches it, leaving the rest of the coffee dry or underextracted. The main reason for this is often not only a mistake in the setting, but also heterogeneity grinding.
Cheap coffee grinders with a knife principle of action or worn millstones produce powder with a large range of fractions: from dust to large pieces. Fine dust clogs the pores, creating high pressure, and large pieces form voids. Water instantly blurs these voids, forming channels. This can be determined by the uneven color of the trickle or by the spotted, holesy surface of the used tablet.
- 🕳️ Reason: The presence of large fractions in the total mass of the powder due to bad millstones.
- 💧 Symptom: Fast strait, splashes from the holder's noses, light spots on the pill.
- 🛠️ Decision: Use of coffee grinders with quality millstones (conical or flat) and regular cleaning of oils.
Distribution techniques are also used to combat this phenomenon, such as the Weiss Distribution Technique (WDT) method, using thin needles to break the lumps before tempering. This helps to level the density of the tablet and minimize the risk of channel formation even with imperfect grinding.
What is WDT and why is it needed?
WDT (Weiss Distribution Technique) is a method of distributing coffee in a holding with thin needles (usually 7-10 pieces). The instrument is immersed in coffee and makes circular movements, breaking the lumps and evenly distributing the particles throughout the volume of the holding. This prevents channel formation and makes the extraction more uniform, which is especially important for carob machines without a vibration distribution system.
Specificity of grinding systems: millstones against knives
Choosing a grain grinding device is perhaps even more important than choosing the coffee machine itself. For carob systems, knife coffee grinders are categorically not suitable, which cut the kernel chaotically, creating heating and an uneven fraction. The only correct solution is grinders, which grind the grain between two surfaces.
The cornstones are conical and flat. Conical millstones are often considered more forgiving for home use, as they heat coffee less and give a good balance of body and acidity. Flat millstones provide maximum uniformity and clarity of taste, allowing you to reveal the subtle nuances of expensive varieties, but require more accurate adjustment and stable voltage in the network.
When choosing a coffee grinder, pay attention to the presence of step-by-step adjustment. For espresso, micrometric setting is important, where one "click" changes the distance between the millstones by fractions of a millimeter. Without such accuracy to get into the narrow window of the correct strait for carob machine is almost impossible.
⚠️ Attention: Change the grinding settings only when the grinder is working (the grinders are spinning). Changing the calibration on the stopped millstones can lead to jamming of the mechanism or breakage of the adjusting screw.
☑️ Checking the boiling readiness
Frequently Asked Questions (FAQ)
Can I use coffee for Turkish in a carob coffee machine?
It's not recommended. Grinding for the Turk (in the dust) will create such a high resistance that the water will either not pass at all, or will push the pill, spoiling the car. The pressure in the group will exceed the permissible norms, which can lead to the failure of safety valves.
How often should the coffee grinder be cleaned?
To maintain stable grinding and taste, it is recommended to dry brush once every 1-2 weeks with active use. General cleaning with special pills or alcohol should be carried out every 2-3 months to remove old coffee oils that give bitterness.
Why does coffee taste different throughout the day?
This may be due to changes in the temperature of the millstones (they are heated by friction and change the geometry of the grinding) or to degassing of grain in the bunker. Try not to keep a large amount of grain in an open bunker all day, it is better to sprinkle a portion on one cooking.
Does the hardness of water affect the choice of grinding?
Indirectly. Very soft water extracts coffee more aggressively, which may require a little more grinding or shorter strait time. Hard water, on the contrary, extracts worse, and a finer grinding may be required to get the taste of the nasa.