Here is a simple question you may have – does your coffee maker bring water to a boil before dripping over the grind to make coffee?
This may be a surprising answer but no, it doesn’t if you are using a regular drip coffee maker.
It gets close but doesn’t go all the way.
If you want to know how hot the water gets it usually around 200 degrees, a bit below boiling.
What is Boiling Water?
Let science answer this question. The difference between hot water and boiling water is a matter of temperature.
Boiling water refers to water that has reached a certain temperature – 100 degrees Celsius or 212 degrees Fahrenheit at sea level. At this temperature, water is exposed to enough heat to cause it to bubbles and create steam. Boiling water is often used to cook food.
Other use for boiling water is sterilization. Boiling water helps sterilize bottles used for canning, feeding bottles for babies and spoons and forks.
Basically the only coffee makers that can actually boil water are alternative heat source style coffee makers like The Farberware Yosemite or the Bialetti Moka Express, both of which are placed directly on a burner or over an open flame.
Percolators aren’t as trendy these days but moka pots are. You can see my favorite stainless steel moka pots here if you like.
Why Doesn’t A Coffee Maker Boil Water to Make Coffee
First of all boiling water is never good for brewing coffee. Hence, it’s why coffee makers do not boil water.
Even in a percolator or a moka pot the steam from boiling water rises and condenses and it’s that that is what brews the coffee. If left unchecked the final brewed coffee can then start to boil and reduce down though so these devices are rarely left to brew coffee unattended.
See this post for details on reducing coffee after it’s been brewed.
A lot of coffee pots these days come with a separate hot water reservoir & dispenser. In fact my wife bought me a decent coffee machine for Christmas back in 2011 and it had a hot water reservoir. She uses it for making hot tea in the morning.
I tested the hot water reservoir not long ago just to see what temp the water came out at. I measured around 190 degrees in my mug meaning that it was probably a pinch higher in the chamber under the heating element.
Many high end coffee makers report their brewing process brings the water temperature up to 200 degrees (the ideal temp for brewing coffee) but even that is 12 degrees under that of boiling water.
For a coffee maker to boil the water the element would have to turn all the water to steam and this is something that they are just not designed to do. To trap that steam and maintain temperature would require engineering a new kind of device, a pressure cooker for coffee so-to-speak.
What is the Perfect Water Temperature for Coffee Makers
Keurig brewers heat up water up to 192°F. This is a few degrees less than the range suggested by the National Coffee Association. But, the company noted that it is the optimal temperature for brewing coffee, cocoa and, tea.
Hula Daddy shared a survey by Consumer Reports and Cooks Illustrated that reviewed coffee makers’ temperature and that most brand new coffee makers have showcase the prescribed water temperature range of 195°F to 205°F.
If you own a new coffee maker, it’s water temperature when brewing is guaranteed to be within the range. But, what if you own an old coffee maker? Say, you bought it last year and you have used it almost everyday. Will it still have the same water temperature?
We have tested a number of used coffee makers and found that after a few months that the brewing temperature drops drastically. One popular used coffeemaker we tested was brewing coffee at 156 F.
Why is There a Prescribed Temperature?
The Kitchn suggested, “195°F to 205°F is the range where water-soluble flavor compounds most easily dissolve in water”.
Cafes maintain this temperature when preparing their coffee. That’s to-go coffee has that just-right temperature and we try to recreate it at home with the help of a coffee maker.
If you are going to spend the time, energy and most importantly, money on making good coffee at home, these parameters are vital to your success based on the scientific research that the SCAA as well as several other foundations have conducted.
All the SCAA certified coffee makers are made to high standards and they all will maintain the highest optimal water temperature at brew time. Of them all I personally like the Cuisinart CPO-850 the best because it is one of the lowest price SCAA certified machines, meaning it is the best value for a top-performing brewer.
What Would Happen if Coffee Makers Used Boiling Water
You could still use boiling water for brewing coffee but it wont yield a good tasting cup. If you were to use boiling water on a stovetop for instance this is what you would notice:
Boiling water burns coffee grounds. High heat burns the coffee grounds and make it taste bitter. This is the real reason why you don’t get the temp all the way to boiling.
How can you Control the Temperature?
There are temperature controlled kettles. But your best partner is a kitchen thermometer.
If you are using a coffee maker, it has a built in water heater and control. Most brewers have thermocouples. Thermocouples are mechanical parts. Over several usage, they tend to wear out. That’s why you still need to check the temperature of the brewer, especially if you had been using it for a long time.
An indicator of a damaged thermocouple is a change in the taste of your brewed coffee. It tends to be sour, it’s time to get a new brewer. The thermocouple is not achieving the desired temperature. As a result, the brewed coffee is “underbrewed”.
Don’t make the mistake adding more ground coffee to mask the taste. A new brewer will serve you better.
If you are using a Chemex or a French Press, heat up the container before using it. Add hot water and let it sit for a few seconds. It will warm up the container and maintain the temperature of the water when you start to brew.
Here are Some Other Reasons Why Your Coffee Maker Hot Water Heater Doesn’t Go Up to Boiling
Out of curiosity I actually went to my stove and started boiling water. During the full boil I picked the pan up and poured the water out into my mug and measured it at 195.
How is that possible I thought. Seems the first bit of temp drops pretty quick when removed from the heat source. It also appears that altitude affects the temperature of boiling water a lot more that I realized in the first place too!
At 4000 feet for instance (like me) water boils at only 204 degrees! If you are at a higher altitude water boils at a lower temperature. Add in the heat loss from removing the water from the heating element and temperature drops quickly.
The problem of heat loss can be mitigated by preheating the cup or pot you are pouring the hot water into but on the other end of the spectrum 212 degree water from a coffee maker is really unlikely because that is the boiling point of water at sea level. As the altitude goes up the boiling point drops. This is another reason why pressure cookers work so well. The increase in pressure actually increases the boiling point of water allowing it to get much hotter than it could under normal circumstances.
So, can you use a coffee pot to boil water?
Yeah, for all basic needs the water coming out of a coffee maker is probably going to be a bit below the temperature of boiling water from your stove or a flame. But then again it’s not likely to be low enough to hinder what you are up to.
If you truly need boiling water 200-212 degree water I suggest using a stove top pan but if 185-190 degree water is fine for your needs then most quality coffee machines will do just fine. Just make sure to clean the pot real good if you want to minimize your chances of getting any residual coffee flavor in your water as it passes through an empty coffee filter basket.
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