The best water temperature for hand-brewing coffee absolutely affects the quality of a cup of coffee.

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Chapter VII

The temperature of brewing water--an essential element of good coffee

The quality of water temperature control absolutely affects whether a cup of coffee can preserve the delicious substances in the beans. The better your coffee is brewed, the trickier the ultimate question of "water temperature" becomes. Water temperature seriously affects the quality of coffee, but water temperature is difficult to control.

The water temperature is not very good, because the espresso machine brewing water temperature is higher than 200 ° F, the water volume is small, and the action of measuring will more or less reduce the water temperature. This "measurement technique affects the measured subject" is an old problem.

So, I suggest you don't measure the water temperature directly. Instead, the temperature is determined using a trial-error-correction method. Use your taste buds as sensors. There is another reason for this: beans of different roasting degrees have different optimal brewing temperatures.

But wait a minute, I'll still use "temperature" as a quantitative indicator to give you an idea. (I used Fluke 51 K/J digital thermocouple J alloy probe, beans baked to a northern Italian deep red brown, no oil on the surface.)

The temperature's wrong.

The ideal water temperature is 203.5 ° F for the indicated head. Espresso is a dark reddish brown when cooked, crema has dark brown spots. (Some Italians call it el tigre, meaning tiger stripes)

The water temperature is too low, and the coffee brewed is brown. Crema is also very thick, smooth and even, but the color is lighter, no dark spots. If the temperature is below 195 ° F, it tastes bitter and sour. This is the worst way to cook my baked beans.

(Please refer to pages 106 and 107 of the original book for comparison photos of ideal and too low water temperatures.)

On the other hand, too high water temperature will burn coffee grease, there will be a "tongue bite" feeling, aftertaste scorching. At worst, crema has thick dark streaks on its surface. If the water is just a little too hot, the espresso will be plain, not bad, but not exciting.

Flavor characteristics are determined by beans. If brewed properly, coffee should smell and taste like freshly ground coffee.

The temperature control is good, and the texture is thick and smooth.

As I mentioned in Chapter 5 (Commercial espresso machines), engineers still have to work hard to control the temperature of the outlet head to win more applause. A lot of espresso machine makers have patents, but I personally think there's still a long way to go.

Water boiler effluent can already be maintained at ±1 ° C fluctuations (equivalent to ±1.8 ° F), but to maintain a stable temperature of the outlet head is another matter. The machines I have tried have at least 6 degrees of variation (equivalent to ±3 degrees).

The structure of the filter handle itself is also responsible. It itself is made of heavy metal for heat preservation. But metal is easy to dissipate heat, take your hand off the machine, put coffee powder, press... During this process, the metal part continuously dissipates a large amount of heat, and eventually the temperature will be 20 degrees lower than originally expected.

I always say,"lock the handle on the machine when it's useless," just to keep the temperature constant. When opening a shop to do business, put coffee powder filter basket, never idle stay on the counter. You walk into an espresso the other day and see the handle of the filter resting on the handle.

Forget it! Go to another cafe!

set temperature

Since it's impossible to measure the temperature of an espresso machine with a thermometer, you have to pay for a digital thermometer that can measure the temperature quickly and accurately with a very light probe tip. For example Fluke 51 Thermometer, if you can get it, refer to my method.

Ideally, the sensing tip of the thermocouple is buried directly in the pressurized coffee cake. In this way, when brewing coffee, you can monitor changes in water temperature at any time. Make a small hole in the bottom of the coffee filter basket just enough to pass through the sensing line, the smaller the hole, the better. (The coffee powder will automatically fill the small hole, not bad!) Lift the probe tip up close to the top surface of the coffee cake.

When most heat exchanger type machines are idle, heat slowly accumulates in the outlet head. Therefore, the temperature will be higher than the set value.

When a machine with a dedicated water boiler is idle, the outlet head temperature will be 3 to 4 ° F lower than the set value.

temperature change

Very careful and complex procedures are required to stabilize the temperature of the water passing through the handle cake. That's the difference between a "good" bar and a "master" bar. It's intuitive, but there are some tricks to be had.

The machine I use, if it flushes out 2 ounces of hot water, throw it away immediately. Then flush out 2 ounces of hot water, repeat the operation, the temperature is almost the same. Use this way to minimize the temperature change of the head. (The basic idea is to keep the idle and operating temperatures of the head as close as possible.) Note: Do not use more than 2 ounces of hot water at a time.

The longer the machine is idle, the more the temperature of the outlet head deviates. The better the machine, the less it deviates.

Commercial espresso machines are designed for continuous use. The more often the machine is used, the more stable the temperature will be.

In Italy, espresso machines with fewer than three outlet heads are rarely seen. The larger the machine, the greater the mass, the more hot water, and the more stable the temperature of the outlet head. To make good coffee, my advice: don't use too small a machine at the bar (no less than three outlet heads).

Keep the handle warm.

If you wait a few minutes before brewing your second espresso, use the time you spend grinding beans to turn on the pump and pump out 2 ounces of hot water to preheat the handle and used coffee filter cake. Let's leave the used coffee powder in the handle before we brew a cup of espresso, no doubt! Because the residue itself is hot, it helps keep your hands warm.

When you remove the handle to refill the coffee powder, act quickly and accurately:

* Knock out old powder, put in proper dosage, compact

* Start the pump and pump out 2 ounces of hot water

* Quick lock handle

* Start the pump immediately.

(Chapter 21,"How We Cook Espresso," will repeat the entire procedure.)

Too much hot water, you're in trouble.

As mentioned earlier, you should knock out the old powder, but there will still be some powder remaining on the filter basket. People in our shop wipe it off quickly with their fingers, but some people turn on the pump and rinse the residue with hot water. This is wrong! Because this will cause excessive fluctuations in the machine water temperature.

Espresso machines are designed to maintain temperature stability as much as possible, but are limited to 1 or 2 ounces of hot water at a time. Using too much hot water at a time is not a good idea to use a machine. So when I say "use hot water," I always stress no more than two ounces.

If the coffee powder forms small hard lumps and adheres, it can be washed with hot water from a steam boiler. There are other benefits: the handle temperature is raised even further.

If you feel that there is a problem with the water temperature of the machine, ask the agent's technician to help adjust the heat exchanger type espresso machine to adjust the temperature of the steam boiler.

Espresso Coffee: Professional Techniques 1996 Edition

Source: Bolan Coffee College