The initial aim in producing any cup of coffee is to release the coffee oils and soluble organic compunds from the coffee grounds into solution in the final cup. Not all the soluble compounds are desirable particularly tannin so it is important to brew the coffee is just the right manner to produce the perfect cup. Although it is possible to extract as much as a third of the mass of coffee from the grounds the optimum amount is about 20% There are six important factors to consider when making fresh coffee. 1/ The coffee grind - By this we mean the particle size of the coffee grounds.
This varies typically from largest to smallest thus: coarse, medium, fine and espresso (or very fine) Over-extraction can occur if the grind size is too small for the method and equipment used resulting in a coffee being bitter and too strong. If the size is too large then under-extraction will occur resulting in a weak wishy-washy coffee. Typically one would use a coarse grind for a coffee pot, medium grind for a cafetiere (French Press), medium to fine for a typical filter drip machine and espresso grind for an espresso machine. 2/ Freshness and quantity of coffee - Coffee beans should be stored in a cool dry place out of direct sunlight and ideally kept in an airtight container. The coffee should be ground to order as ground coffee will lose some of its subtle flavours and aromas if is left exposed to the atmosphere for very long.
It is vital to use the recommended dosage of coffee depending on the equipment being used. Increasing the brewing time, but using less coffee will not work very well but produce an over-extracted beverage. Using more coffee than recommended but a quicker infusion time will result in an under-extracted coffee. 3/ Temperature and water quality of the water - Always use fresh cold water to start off the brewing process.
Ideally the water should be filtered to remove unwanted taints and odours and be very slightly hard. Ideally water that is between 94 and 98 degrees Celcius should be used - not boiling water. If the water is too hot the coffee grounds can be scolded imparing the flavour. 4/ The infusion time - The length of time that the hot water is in direct contact with the coffee grounds is crucial in producing the perfect cup. In reality this is determined by the equipment being used to brew it, so always follow the manufacturers guidelines. As a rough guide however consider the following.
10-30 seconds for espresso grind 3-6 minutes for fine grind 6-8 minutes for medium grind 8-10 minutes for coarse grind 5/ Brewing method employed - Basically there are three different methods employed to make coffee. These are steep & strain, filter infusion and pressure infusion. Steep and strain simply involves putting hot water in contact with coffee grounds in a pot or container until under extraction has occurred.
The resulting brew is strained to isolate the coffee liquor. Filter infusion is common in many applications and uses a filter basket filled with coffee grounds that has hot water added from above. The infusion time is relatively short as the water infuses briefly with the coffee until the liquor passes thought the basket into a flask or container below. Pressure infusion - Hot water is forced under high pressure though a small tablet of compacted grounds to produce an individual serving of coffee. This is the standard method of producing espresso.
Again it is imperative to use the right method with the correct type and grind of coffee. 6/ Cleanliness - Coffee contains oils that will leave a tarry residue on equipment that can contaminate and spoil the taste of subsequent brews. Daily washing and cleaning of equipment is an absolutely vital part in producing the perfect cup.
Have fun - producing a great tasting cup of your favourite coffee should be an easy and enjoyable task.
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