Monday, December 03, 2012

Coffee Week - How to brew the perfect cup of coffee

In the first part of our Coffee Week blog series, Edward Grace tells us how to brew great coffee.

To brew great coffee is not difficult, but it does require some basic principles to be observed:

Coffee

Use good fresh coffee. It is best to grind your coffee right before brewing. Burr grinders are the best.

Coffee to Water Ratio

Use 6 g of coffee for every 100 ml of water - this is a good starting point. Using simple kitchen scales for this is the best. You may want to upsize the water quantity slightly (up to 10%, not more), to allow for retention of water in the grinds at the end of the brewing process.

Brewing Water Temperatures

Ideal water temperature for brewing coffee is 92-93 degrees C. In most of hand brewing methods, the water is boiled and then left to cool. Using a kitchen thermometer will help you find the right point to start brewing your coffee. Allow for the fact that as your brew your coffee the temperature of your water will be gradually falling. Starting brewing when the water temperature just dropped below 94 degrees C should give you a great brewing temperature range.

Brewing Time

The ideal brewing time is between 3 and 5 minutes. Extending brewing time beyond 5 minutes will make your coffee taste increasingly bitter. Shortening the brewing time will result in under-extraction and coffee tasting thin. 4 to 4.5 minutes brewing time is ideal.

Whole Beans or Ground Coffee?

Whole beans. Ground coffee loses its freshness incredibly fast. Grind your coffee right before brewing. A decent electric powered burr grinder can be bought for as little as £40. We like the Krups Expert Grinder (£39.99 in kitchen capers in Windsor) and the more expensive Cuisinart Auto Burr Grinder (£60 at kitchen capers in Windsor).

Little hand grinders such as the iconic Skerton Grinder by Hario or its twin brother by Tiamo (available for £29.99 at Tastes) are even less expensive and, if you are prepared to work a little harder (physically, that is) for your perfect grind, are capable of beating anything electric with a price tag below £100. Blade grinders are not ideal, as they make it very difficult to control the size and the consistency of the grind.

Water Quality

Considering that the strongest cup of coffee is more than 98% water, the quality of water used for brewing is very important. Use fresh chlorine-free soft to medium-hard water with total dissolved solids value (tds) of one hundred and fifty or less. Ideally, the water used in brewing should be pH neutral (about 7 value). Acidic or alkaline water will interfere with the balance and flavour of your coffee. If you have to brew coffee using more alkaline water, it is best to use light roasted coffee, conversely, with more acidic water, darker roasted coffees perform better than the light roasted ones. Generally, if the tap water is of unacceptable quality (which is probably the case for most of South East England), consider using bottled water, but pay attention to it TDS and pH balance. Out of well known bottled water brands that are readily available in the UK we find Volvic and Stretton Hills to be of acceptable quality.

Putting Principles to Good Use

One of the most simple and elegant solutions to making a great coffee at home is using a Melitta style brewing cone and paper filters. Manual drip or a pour over method, as it is commonly known, is one of the simplest brewing methods preferred by many a connoisseur. Tiny droplets of water flow over the coffee grounds extracting all the oils and flavours that make a perfect brew. As with any brewing method, the key parameters should be observed: your water should be 92-93 deg C, you should allow 6 g of coffee per every 100 ml of water (perhaps allowing a little extra - not more than 10%), and the brewing time should not exceed 5 minutes. Follow the simple steps below to make your perfect cup of coffee:

1. Boil the water.

2. Put the paper filter in the dripper cone and pour some hot water through the paper filter (this will prevent any hints of paper taste in your coffee).

3. Discard the water used to pre-wet the paper filter.

4. Place the required amount of ground coffee into the filter.

5. Making sure that your boiled water is the right temperature (93 deg C), slowly pour the water over the grounds in a circular motion. Do not pour more water than is required to cover the grounds - let the coffee bloom and the resultant foam to rise and fall.

6. Pour more water to cover the grounds, repeat this step several times until you have poured the required amount of water.

7. Once all the water has dripped through the grounds, remove and discard the filter.

8. Stir the brew to ensure the even consistency of taste and serve.

9. Enjoy!

Tip #1: Using kitchen scales is a great way to control the amount of water used in brewing. Right before you start pouring water through the coffee grounds, place your brewer (with coffee grounds in the filter) on the scales, set weight to zero and start pouring. Continue pouring water until the indicator on the scales shows the required target weight.

Tip #2: Time your extraction (e.g. brewing) time. If it is too fast, grind your coffee finer, if it is too slow, grind your coffee coarser. Target 4 to 4.5 minutes brewing time and once you are in it, remember the setting on your grinder and keep it. Be prepared for different coffees to brew slightly differently, but, generally, if you are using a drip method, frequent changes of setting on your grinder are not necessary.

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