Coffee Roasting at Northern Tea Merchants

Here at Northern Tea Merchants we roast coffee daily. You cannot buy coffee fresher than ours. We possess two coffee roasters, one of which is used to prepare samples and has only a 227g capacity.

Our main roaster, originally built in 1959, now modified extensively to our demanding specifications, roasts 70kg in approximately 20 minutes, and produces no roast smoke due to an afterburner we fitted in 2000. We regularly roast over 1 tonne of coffee per day!

The Coffee Roasting Process Follows this Pattern…

  • The green, unroasted coffee beans are loaded into the Entecon lifter and conveyed into the upper hopper of our roaster.
  • The loading hopper door is opened, allowing the green beans to enter the rotating inner drum.
  • Flame is applied to the drum, allowing the beans to commence roasting. (The two gas burners that we use apply approx. 50kW per burner of heat to the drum, bringing 70kg of coffee to optimum temperature (190 – 200°C) in about 20 minutes!)
  • During the roasting process, regular samples are taken from the drum to verify the depth of roast of the beans. Every sack of coffee roasts differently. This can be due to the differing water content in coffee beans, bean size, the time of year at which the bean was harvested or how long the bean has been in storage before it arrives at Northern Tea Merchants (see Old Brown Java, for example).
  • Once the beans are roasted as desired, they are ejected into a cooling tray. It is important to cool coffee beans very rapidly as when they are first ejected, they are so hot that coming into contact with air can make them catch fire! The cooling tray works on the principle of rotating arms that ‘stir’ the coffee. This keeps the beans moving so they do not ignite. A system of air ducts in the base of the tray also pulls cool air through the roasted beans.
  • Once cooled, the coffee beans are loaded into either our coffee bins in the shop, for sale to our many satisfied retail customers, or are immediately ground, packed and distributed by our vans to many hotels, restaurants, cafes and bistros, Stately Homes, wholesalers and retailers and other commercial outlets throughout 100 mile radius of Chesterfield.

Coffee Defect Score Sheet

The Green Coffee Association of New York has published a scoresheet that is universally used for grading coffee by its defects.

Coffee is an agricultural product and is NEVER 100% perfect.

A system for the universal grading of coffee by using defects to count towards an overall score and type classification was developed by the Green Coffee Association of New York and is now used universally by all brokers and importers for grading the coffee they buy.

Although it is technically possible to produce a zero defect coffee, the resulting wastage of coffee beans makes the price very high (or more than many people are willing to pay for coffee).

At Northern Tea Merchants, we buy coffees with low defect scores, usually type 2 or 2/3 depending upon availability and the actual cup profile of the beans in question.

The proof of the pudding is in the eating – and we are sure you will enjoy our range of excellent quality, well-roasted coffees!

COFFEE DEFECT SCORE (as set by The Green Coffee Association, New York, USA)

1 Black Bean = 1 Defect

2 Sour Beans = 1 Defect

2 Parchments = 1 Defect

3 Shells  = 1 Defect

5 Quakers = 1 Defect

5 Unripe Beans = 1 Defect

5 Broken Beans = 1 Defect

2/5 Eaten Beans =1 Defect

1 Pod = 1 Defect

1 Large Husk = 1 Defect

2/3 Small Husks = 1 Defect

1 Small Stone = 1 Defect

1 Medium Stone = 2 Defects

1 Large Stone = 5 Defects

1 Small Twig = 1 Defect

1 Medium Twig = 2 Defects

1 Large Twig = 5 Defects


6 Defects equal type 2

9 Defects equal type 2/3

13 Defects equal type 3

21 Defects equal type 3/4

30 Defects equal type 4

45 Defects equal type 4/5

60 Defects equal type 5

90 Defects equal type 5/6

120 Defects equal type 6

180 Defects equal type 6/7

240 Defects equal type 7

335 Defects equal type 7/8

450 Defects equal type 8

What Drinks Can Be Made Using An Espresso Machine?

  1. ESPRESSO. A single demitasse of Espresso Coffee, black, usually drunk with sugar. Espresso can be flavoured with a drop or two of almond or tangerine extract.
  2. ESPRESSO ROMANO. A demitasse of espresso served with a twist or a thin slice of lemon on the side.
  3. DOUBLE or DOPPIO. A full six ounce cup of straight espresso. To be drunk only by veteran espresso bibbers, early in the morning, before a 12- hour workday and a long evening.
  4. CAPPUCCINO (French: Café Crème) About one third espresso, one third hot milk, topped with one third foam, in a heavy cup. Like the others, usually drunk with sugar.
  5. CAFÉ LATTE. (French: Café au lait; Spanish Café con leche) One or two shots of espresso; and three times as much foamed milk, in a big bowl or wide mouthed glass. This is the favoured breakfast drink of southern Europeans. Café Latte has a greater proportion of milk to coffee than a cappuccino, and tastes weaker and milkier. Strictly speaking, the milk and coffee should be poured simultaneously, one from either side of the bowl.
  6. ESPRESSO MACCHIATO. A demitasse of espresso marked (‘macchiato’) with a small quantity of hot foamed milk.
  7. LATTE MACCHIATO. An eight or ten ounce glass half filled with hot foamed milk, into which a demitasse of espresso is slowly dribbled. The coffee will colour the milk in faint, graduated layers, darker at the top, shading to a light at the bottom, all contrasting with the layer of pure white foam at the top.
  8. MOCHA. Not to be confused with Mocha – Java, a traditional blend of Ethiopian and Indonesian Coffees. A ‘mocha’ to an espresso aficionado is about 1 third espresso, one – third strong, unsweetened hot chocolate, and one -third steamed milk. The milk goes in last, and the whole thing is usually served in a mug. Voltaire is said to have consumed 40 cups of Mocha a day at the Café Pro cope. Some cafés garnish the foam of the cappuccino and café latte with a dash of unsweetened cocoa, which adds the subtle perfume of chocolate to the drink. Others use cinnamon, but cinnamon can give too distinctive a flavour and is to some people out of harmony with the dark tones of the coffee. Straight espresso is delicious with whipped cream (con panna), but topping a good, foamy cappuccino with whipped cream is as pointless as putting ketchup on spaghetti.