This page is - Great features - Brew temperatures

Brew Temperatures.  Lord, we don't half get into trouble for some of our features - it is perfectly correct for us to report that one of the biggest issues in the espresso market in the last few years has been the question of precision of temperature at the brewhead.    What gets us shot at is suggesting which of the espresso machine makers brought up the question first.   As we talk to them all regularly, we can state with absolute certainty - they were all first!

This feature was for Caterer and Hotelkeeper.

Get your green tea temperature wrong and you're in big trouble!

The news that Marco Beverage Systems has been working with barista champion James Hoffmann  to create a new kind of super-controlled water boiler has stirred the beverage sector, and brought back to attention the importance of brewing temperatures.

This is something widely debated in espresso coffee, but often missed everywhere else – most staff still heat water to boiling, which is not necessarily right for tea, and can ruin cafetiere coffee.

The danger was neatly described recently by, of all people, the AA’s top repair patrolman, judging a roadside café contest. He reported: “About 70 per cent of cafes got it right, with tea that was ‘sippable’ to start with, and we could drink it immediately or within a couple of minutes.” 

The worrying thing is that thirty per cent got it wrong.

There are two considerations in beverage temperature – one, which even Saturday staff can understand, is that a too-hot drink is uncomfortable. The other is that one degree either way can completely change the character of tea or coffee being served.

In tea, one big hazard is the general belief that it should be made with a ‘rolling boil’, of  large bubbles in turbulent water. The second is of espresso-machine salesmen who recite the standard phrase that ‘the machine will produce boiling water for tea’.

All tea should not be brewed at boiling point. A fine green tea should be brewed very low, maybe as low as 70C, while a white can be brewed at 80C, and oolong a little higher. Black tea can be hotter, but arguments rage over how much - even the Tea Council says that water must be ‘boiling’, and agreement comes from two very unlikely allies, Teapigs and Tetley.  (Teapigs is the deliberately irreverent company which set out to prove to consumers that discovering the world’s great teas can be fun, and which generally disapproves of conventional tea-bags.) 

“There is no getting away with it,” says Teapigs’ taster Louise Allen, “black tea requires freshly drawn water at 100 degrees – no debate about this one. And nothing beats a temperature-controlled kettle, because although some catering boilers can manage 100 degrees, the water sits in the tank for some time and is repeatedly bought to boiling point, which is not good for tea.”

At Tetley, brand development manager Peter Haigh also believes in boiling-point: “The hotter the water, the faster the leaves open and the better brew you achieve. It is not always feasible to use freshly boiling water in the hospitality industry, but we do recommend that you use water as hot as possible.”

However, Teapigs and Tetley are in a minority.

Jane Pettigrew, probably the most famous of all Britain’s tea teachers, sets the figure lower: “All black teas should be brewed at the same temperature, but given different steeping times – about a minute longer for a larger leaf tea. For black teas, set your boiler at 95-96C.

“So a catering area really needs two boilers, with the other at 70-75C, and these will be fine for pretty much all teas. If it is not possible to have two, then for white and green teas, train staff to draw off some water from the 95-96C boiler and put it into a jug to cool – use a thermometer to check that the water is adequately cooled. If customers ask about the wait, train staff to explain about making the perfect pot of tea.”

That thermometer is vital, agrees Andrea Stopher, trade marketing manager at Twinings. “For greens, whites and oolongs, boiling water is too harsh on the leaf and brings out the bitter tannin taste rather than the soft, sweeter character. Have your staff taste a green Sencha brewed at 90C, and then one brewed at 70C – they’ll quickly understand why a thermometer is an essential piece of catering equipment!”

At Mighty Leaf, one of the companies which has pioneered the new kind of big tea-bag suitable for large-leaf tea, managing director Alan Mellor believes in water just off the boil.

“Even the very highest of high-end hotels have practical difficulties with this. It is the grade of the black tea that is significant – many tea-bags are either dust or at best fannings, and these small particles have a huge surface area and infuse very quickly, hence the flat taste.  Leaf tea infuses more slowly, and hence the much more complex flavours.

“We always stress that green and white teas should definitely not be made with boiling water. A practical tip is to put boiling water into a cold jug and then into the cold pot with the tea - it will be about right.”

And do not draw water for tea from your espresso machine, says Steve Penk, marketing director of La Spaziale espresso machines. “The idea that an espresso machine also provides hot water for tea comes from sales people who don’t know a thing about brewing parameters.

“The water comes from the reservoir of an espresso machine, and it is supercharged, so it comes out at about 120C – far too hot for tea.  Don’t do it unless you have a bypass on which you can set the water temperature.”

(There is another reason for cooler tea. The British Medical Journal reports Australian research that drinking a great deal of tea, too hot, increases the risk of cancer of the oesophagus.  The Queensland Institute of Medical Research commented: “We should follow the advice of Mrs Beeton, who prescribes a 5-10 minute interval between making and pouring tea.”)

In the coffee sector, a similar problem exists. There is still a tendency for some catering staff to bring water to the boil and slosh it into a cafetiere, whereas the Marco/Hoffman theory, for the machine dubbed the ‘uber-boiler’, dictates that every coffee has a ‘sweet spot’ which should be recognised and respected. 

“When I first started in this business, I was taught that you ‘take the pot to the kettle for tea and take the kettle to the pot for coffee’,” says David Latchem managing director of Café du Monde.  “It was simplistic, but illustrated the point that tea requires slightly hotter water than coffee. Water straight from the kettle is a degree or two below boiling, but by the time you have taken it to the coffeepot, it is in the region of 96C.”

By comparison, the Bunn 392 pourover is set to brew at 92C, and First Choice suggests brewing filter coffee at 92-94C. Rombouts says its One Cup filter coffee should be brewed at 93C, and comments that a margin of plus or minus three degrees is probably reasonable before the consumer notices a difference in taste.

But not in espresso.

“A difference of half a degree in espresso is noticeable to just about everybody,” says David Cooper of Cooper’s in Huddersfield, whose promotion of temperature control in Dalla Corte espresso machines started a major debate in the café world. “Grab a man off the street, give him espressos at 89C, 89.5C, and 90C, and he will be able to tell you there is a difference.  And one degree makes an even more radical change, so this is not just a matter for coffee geeks!

“Having said that, with a good coffee blend, you’ll find that 92C isn’t a bad yardstick.”

Tristan Stephenson, a trainer for Diageo and former bar manager for Fifteen, and a finalist in this year’s barista championship, recently confirmed this more dramatically. He was testing a blend of Colombian, Honduran and Sumatran supplied by Origin coffee of Cornwall, serving it at 91C – until he started playing.

“We altered in steps of 2C at a time.  At 86C the difference was drastic - the acidity of the blend dropped and was replaced by an earthiness of sweet warm soil, because the lower temperature was highlighting this characteristic of the Sumatran Lintong in the blend.   At 88C, that earthiness turned to fruity nuttiness.

“At 90C the South American in the blend was beginning to take over with a lightness and more punchy acidity.  At 92C, I was shocked at how light it had become, and we were losing the earthiness of the Sumatran. We eventually found the best balance at 89C.”

The differences even shocked Tristan Stephenson, an experienced championship finalist in espresso.

“I simply could not believe how black and white the results were - I was thrilled to discover the amazing difference that a couple of degrees can make to a coffee.”

And that, say the experts in both tea and coffee, illustrates what every caterer must do regularly – test and taste at different temperatures to find the ‘sweet spot’ of your house coffee and your teas, and then stick to it. Without doing so, you may serve so-so drinks – but doing so, you may serve great ones.

Tristan Stephenson, formerly the barista at Jamie Oliver's restaurant Fifteen, who graphically illustrated the difference that brew temperatures make to espresso coffee.