In a few steps to Home Barista
If you have purchased a new Graef sieve carrier espresso machine or coffee grinder e.g. the contessa or the CM 802, the first use, despite studying the operating instructions, usually raises some questions. In the following we would like to give you some tips & tricks to help you acquire the skills to prepare your personal, optimal espresso in the shortest possible time and thus become a Graef "Home Barista".
Graef CoffeeKitchen - Handmade Coffee Tutorial
For newcomers, it is important to know how the grind setting affects the taste of the espresso.
The grind setting ultimately determines the surface size of the individual coffee grounds. The larger the surface area, the more substances the brewing water can dissolve from the coffee powder.
A fine and even grind is recommended for an espresso. You must ensure that the grinding is not too fine, otherwise no or hardly any water can penetrate the ground coffee.
If the beans are ground too coarsely, the water will run through the ground coffee too quickly. In both situations, the aromas cannot develop properly and you cannot enjoy the full espresso taste.
It is sometimes necessary to correct the milling degree after a certain time, as the texture, moisture content and freshness of the bean are highly dependent on the environment.
This can be quickly corrected by trying out and adjusting the grind or the contact pressure, for example, if the espresso flows into the cup too quickly or too slowly.
For the reasons mentioned above, a high-quality coffee grinder is recommended, as is a high-quality espresso bean.
Make sure that the mill does not consist of rotating cutting blades. These cut the beans into uneven pieces. This results in an uneven grinding degree or unnecessary heating of the bean during grinding and therefore no tasty espresso.
If possible, the coffee bean should be "broken" evenly. This is best achieved with a cone grinder (made of stainless steel), such as the Graef coffee grinders CM 800, CM 900, CM 802 and CM 702.
The coffee bean must not be heated too much during grinding and the resulting friction, otherwise a large part of the aromas will evaporate during the grinding process.
Which coffee is best suited for espresso?
We recommend that you grind coffee beans with a coffee grinder always fresh and in the quantity just needed, e.g. with the Graef coffee grinders.
The aroma of a coffee bean is best preserved if the bean is ground just before the espresso is made.
Each coffee bean has its own characteristic taste. By grinding immediately before preparation, the sieve carrier espresso machine can reproduce the almost full flavour volume of the bean.
This is the difference to ready-ground, commercially available espresso powder, which is usually used in conjunction with espresso makers. This ground coffee has already lost many of its aromas.
We recommend the coffee beans from the Graef "Coffee Selection", e.g. the "Roma"type of espresso. This selected blend of 47% Arabica beans and 53% Robusta beans is ideal for making espresso. This blend has a velvety crema and is harmonious in taste, strong with full body.
Coffee beans for espresso are roasted darker than those for normal (filter) coffee. Otherwise the acids would dissolve too quickly at the very high brewing pressure of a sieve carrier espresso machine. The longer the roasting lasts, the more the acidity drops and the bean gets more body.
Coffee beans from Graef can now also be conveniently ordered from our online shop.
How should the ground coffee be dosed and prepared in the sieve carrier for the preparation of espresso?
The dosage of ground coffee into the sieve carrier depends on personal taste and the size of the sieve insert.
The Graef espresso machines are delivered with two filter inserts for one cup (approx. 7 g coffee grounds, this is only a guideline!) and two cups (approx. 14 g coffee grounds, this is only a guideline!) of espresso.
As an initial guide value, the filter holder or filter insert can be filled slightly "heaped". Then spread the ground coffee evenly in all directions in the filter holder by smoothing it with your index finger.
Now take the tamper and press the ground coffee into the sieve insert.
The contact pressure for the so-called "tamping" should be approx. 15 kg (this can be practised with a personal scale), whereby the tamper should be applied evenly and straight from above.
In this way a straight, evenly compressed surface of the coffee grounds can be achieved and the water flows evenly through the coffee grounds at the optimum pressure of approx. 9 bar.
What should the optimal espresso cream look like?
The result after extraction is optimally a dark to golden brown, dense crema, which is decisive for the formation of the espresso aroma. The quality of the crema can vary depending on the roasting and blend of the coffee beans. For example, bean blends with a higher Robusta content produce a more voluminous crema. The appearance of the crema also depends on these factors and the age of the beans.
To find out whether you have achieved the right consistency in the crema, you can carry out a "sugar test". If sugar sinks slowly into the espresso and does not sink directly, the crema has the right consistency. If this is not the case, this may be due to several factors.
How long should the extraction time take?
A simple espresso should ideally be prepared with approx. 6 - 7g coffee grounds and extracted within 25 - 30 seconds (These are the optimal conditions for an espresso. This is therefore an approximate guide value.)If this is not the case, the grinding degree or the contact pressure should be adjusted when roping.
Depending on the water flow time, a so-called under- or over-extraction can occur. Over-extraction causes too many bitter substances to be released from the coffee grounds. This leads to a very dark crema. In addition, the espresso has a very bitter and burnt taste. Under-extraction causes too few aromas to be released and the espresso therefore tastes very flat/thin and has a very light or no crema at all.
If the espresso flows evenly, slowly and creamy "like honey" from the spout into the cup during extraction, the espresso has the optimal consistency and crema.
How much water should an espresso have?
A good espresso with approx. 6 - 7g coffee grounds should be prepared with approx. 25 - 30 ml water.
A double espresso ("Espresso doppio") with approx. 12-14 g coffee grounds has a volume of approx. 50 - 60 ml
With our sieve carrier espresso machines you can either determine the flow rate (depending on the model) manually (start/stop by pressing a button) or program it freely for 1 or 2 cups (factory setting: 30ml, 1 cup and 60 ml, 2 cups).
What role does water quality play?
The water quality is very important, as coffee consists mainly of water. Mineral water should not be used, as this neutralises the fine acids in the coffee.
Depending on the degree of hardness and the PH value of the water, you may have to regulate the water quality with water filters or, in the case of harder water, decalcify the machine all the more frequently to ensure the machine's longevity. In general, the machine should be cleaned and decalcified regularly.
For an optimal espresso, we recommend water with a pH value in the range of 7 and a water hardness of approx. 8°dH.
Please enquire at the public utility company responsible for your region about the respective composition of tap water.
How high should the water temperature be?
The right temperature is very important so that the water can dissolve all the aromatic substances and as few bitter substances as possible from the coffee grounds in the short time available.
For a good espresso, a brewing temperature of approx. 93°C is ideal((measured at the brewing head!). Boiling water and therefore temperatures above 96°C dissolve unwanted bitter substances from the coffee grounds and the espresso tastes bitter. Too low temperatures below 88°C remove too few aromas from the ground coffee and the espresso tastes "flat".
In general, the following can be said about the roasting and blending of the coffee beans:
- Darker roasts tolerate higher brewing temperatures of around 95°C. The same applies to blends with a higher Robusta content.
- Lighter roasts or sensitive Arabica varieties should be prepared at temperatures around 90°C.
Furthermore, it is very important that the complete brewing system (thermoblock, brewing head and also the sieve support) is pre-heated. Our sieve carrier espresso machines are ready for operation after only a few minutes. However, we recommend that you first cover the machine empty with the sieve support clamped in place, then dry the filter sieve and start the grinding process.
How high should the water pressure be?
The water pressure for an espresso is ideally around 9 bar to ensure optimum extraction. The maximum pumping capacity of many screen carrier espresso machines is usually much higher, at about 15 - 16 bar. However, the water pressure on the ground coffee directly at the brewing head is decisive, which ideally always has to transfer approx. 9 bar.
With the help of the manometer on the Graef sieve carrier espresso machines (except ES 70/80/81) you can already check during preparation whether you have used the correct grinding degree, the correct grinding quantity and the correct contact pressure. If the display is in the yellow or orange (ES85/86) pressure range, the above factors match and you get a good espresso result.
If the pressure display is below or above this range, this is called under- or over-extraction and the factors grinding degree, grinding quantity and contact pressure must be coordinated again.
How is an espresso served?
The cups in which an espresso is served should always be pre-heated, e.g. on the hot plate of your espresso machine. In addition, you should always preheat the cups using the hot water lance by adding hot water. This is important so that the espresso stays hot and the crema does not dissolve too quickly. Furthermore, the cups should be thick-walled and have a filling volume of approx. 25 - 30 ml (double espresso, approx. 60 ml).
A spoon and granulated sugar are served with it. Lump sugar is not suitable as it does not dissolve well in espresso.