Many variables go into brewing coffee, and temperature is one of the most important ones.
However, a basic understanding can go a long way. So let’s start with that.
Typically espresso is brewed between 90-96 °C (194-205 °F).
There is plenty of data that suggests a higher brew temperature will result in a higher extraction yield.
If you aren’t familiar, extraction means “the amount of coffee solids pulled”.
Therefore, temperature and extraction yield relates to roast level in a way where you have to consider the flavor profile you are looking to acquire from the espresso shot.
However, temperature isn’t the most challenging part to adjust; the hardest part is figuring out how it relates to the specific coffee you are trying to brew.
Aspects like roast age and roast level affect how the brew temperature will interact with the coffee during extraction.
Roast degree and temperature
For instance, if you have an underdeveloped/light roast coffee, you may want to brew at a higher temperature to provide a fuller body and sweetness. This will counteract the acidity and “brightness” that may occur.
However, you risk bringing out undesirable traits like bitterness and heavy mouthfeel if the temperature is too hot or the shot is pulled too long.
The opposite could be said for a medium to darker roast coffee. Instead, you could brew the coffee at a lower temperature to bring out more delicate notes and needed acidity.
In terms of roast age, the temperature will affect how gases are released from the coffee during the brewing process. Higher temperatures with fresh coffee will result in more gases being produced. What that does to the coffee during espresso pulling is that more bubbles will occur, and the total pull time might be on the longer side. However, once the espresso starts to flow, it will be faster than an older coffee.
In an espresso recipe, you may have the same brew time between a freshly roasted coffee and an older coffee, but if you split the process into two parts, the fresher coffee will start slow and end fast, while older coffee will have the adverse effect.
Espresso at home — what if you don’t have a PID?
Three types of temperature control can be found within espresso machines. There are mechanical thermostats, pressure stats, and something called a PID, which stands for Proportional Integral Derivative.
- Mechanical thermostats will turn on and heat until 100 °C (212 °F). Once that temperature has been reached, the thermostat will turn off. The downside to this temperature control is that the boiler can only be reheated once it has reached a certain cooling point. In reality that means that your brewing temperature will fluctuate.
- Pressure stats don’t use heating to reach temperature; instead, pressure is used. Lower pressure will mean a lower temperature, while a higher pressure will equal a higher temperature. These tend to be better than mechanical thermostats because tighter gaps leave less room for error when trying to hit the desired temperature.
- PIDs will reach a set temperature and will continue to turn on to maintain that temperature. This is the most consistent and precise technology. PIDs are especially potent in dual boiler machines, because they allow separate boiler temperatures for both steaming and brewing.
What is Temperature Surfing? 🏄
Temperature surfing is a common technique among coffee geeks who don’t have an espresso maker with PID.
Essentially, temperature surfing means that you try to manipulate the machine to either increase or decrease the temperature, depending on your goal.
For instance, an espresso machine may run hot so the user could turn on the group-head, run water, thus causing it to cool down to allow a more desirable temperature to be used before pulling a shot.
On the other hand, a machine might sit on the cooler side and needs to have water run through the group-head to warm it up and bring it to a proper brewing temperature.
Unfortunately, temperature surfing varies and is inconsistent, so sharing tips between at-home brewers isn’t easy unless you have the same model.
A PID is genuinely the way to go for at-home brewing if you are concerned with having one less variable in trying to pull great-tasting espresso consistently. The other two options are doable, but I would recommend doing extensive research on the machine as a whole and being sure to pay attention to the temperature heating elements as you find out more about it.
Temperature at work in a coffee shop
As far as working as a barista in a coffee shop, I personally have never experienced changing the temperature on an espresso machine. Most often, a technician deals with the machine to its specifications.
Changing the temperature isn’t an ideal move because most shop espresso machines have multiple group heads, which would mean having to adjust the temperature multiple times throughout the day. However, keeping the temperature the same on the machine will add consistency amongst the other variables that get changed when dialing in espresso.
Basic variables that get changed are the coffee dosage, the amount of coffee dosed out, and the time it takes. Other aspects that come into play are: the type of grinder you are using, the temperature inside and outside the store, the weather outside, and the amount of sunlight exposed to the coffee. As those aspects change throughout the day, baristas also have to maintain a recipe by dialing it in several times. With that in mind, adjusting the temperature would add an unnecessary step to the grand scheme of providing efficiency.
With all this to consider, simply put, common sense can be used if you understand what has been explained above and how temperature affects coffee when being pulled as an espresso.
Higher temperatures will garner you higher extraction with increased body and sweetness but an increased chance of getting a bitter cup. Conversely, lower temperatures will bring less extraction, more acidity, and less body.
Temperature is an interesting variable to try and figure out. If you are struggling to dial in your coffee on your espresso machine and all the other variables are correct, then temperature might be that last hurdle keeping you from the perfect cup. On the other hand, if your dosage in, out, and time are all good, your grinder is consistent and reliable, and your tamping is good, try adjusting the temperature.
Also, this can apply to brewing pour overs as well. Don’t feel left out if you don’t have an espresso machine at home and want to try and test this.
The needed temperature for coffees will change but should stay in the window of 90-96 °C (194-205 °F
Yes. Having water too hot for espresso will cause it to extract too quickly. The coffee isn’t given the space to develop and will leave you with a bitter cup when that happens.
There could be a variety of reasons why. A simple fix could be that the cup your espresso is being pulled into is cold, and the cup is absorbing the heat from the espresso. Another reason could be because the portafilter hasn’t had enough time to heat up within the group-head. Another more significant reason could be that your espresso machine water boiler for your group-head wasn’t set to the necessary temperature to pull your shot of espresso properly.
As a barista, I steam milk to 71°C (160 °F) for a latte. A good gauge is by using your free hand to tell how hot it is. A latte will be at temperature at a one-second handhold on your palm. If you can only hold your palm to the pitcher for a single second before it’s too painful, then you’re about right. Latte milk texture should be thin microfoam.