This post contains affiliate links.
Having trouble recreating that perfect cup of Vietnamese coffee at home? Maybe your brewing temperature is off. I’ve had to learn that the hard way. Here’s what you need to know.
Vietnamese coffee is brewed with water going into the filter at 190-195F (87-90C). That’s best for a traditional Vietnamese blend that has a dark roast and is mostly Robusta beans. If you’ve got a higher quality coffee that’s roasted a little lighter, you can increase the temperature to 205F (96C).
For more information on the right water temperature and what happens if you get it wrong, keep reading.
- 1 Right water temperature for Vietnamese coffee
- 2 How to get the right temperature
- 3 What happens if the water is too hot?
- 4 What happens if the water is too cold?
- 5 My coffee is cold!
- 6 Favorite Vietnamese Coffee Products
Right water temperature for Vietnamese coffee
The right water temperature does depend on the method you use to make coffee. For Vietnamese coffee, you’ll likely be using a Phin (Traditional Vietnamese filter). That’s the best way to do it and gets the most authentic results.
So what’s the right temperature for this way of making Vietnamese coffee?
It does depend on the type of coffee you’re using and especially the roast.
- Dark roast Robusta: 190 to 195 degrees Fahrenheit (87 to 90 degrees Celsius)
- Lighter roast: 200 to 205 degrees Fahrenheit (93 to 96 degrees Celsius)
Traditional Vietnamese coffee is never going to have a very light roast. It’s dark or slightly lighter. Why can you use a higher temperature for the lighter roast?
The dark roast is likely going to be (mostly) Robusta beans. Robusta beans have quite a few compounds in them that don’t taste all that good. That means you don’t want those in your brew. With higher temperature water you extract more of those compounds which means a worse taste.
When you use a lower water temperature, you’ll still extract most of the caffeine and fewer of the bad tasting parts. Won’t you have less taste? Yes, slightly but Robusta has a pretty strong taste to start with so it’s not a big problem. Even at a lower temperature you’ll still have a similar ‘amount of taste’ than other types of coffee.
The lighter roasted beans tend to be higher quality. Higher quality beans have fewer of the compounds that make a coffee taste bad. Which means you can use hotter water. Often this will be a blend of Arabica and Robusta beans or mainly Arabica. Arabica beans are getting grown more and more in Vietnam but are also imported. So while traditionally, Vietnamese coffee is almost exclusively Robusta, that’s changing.
If you buy a bag of ground Vietnamese coffee in the supermarket, it’s likely going to be largely Robusta coffee. There’s nothing wrong with that but it means you should let your water cool down slightly longer to 195f/90c
Most bags of coffee will tell you which types of beans are in there but not in which ratio. However, price tends to be a good indicator. If not for the type of beans then it does say something about the overall quality. With higher quality coffee, you can get away with higher temperatures without it tasting bad.
With the ‘right’ temperature I mean the temperature at which you pour the water into the filter. Of course it’s going to cool down while brewing and waiting for the brewing to be finished. That’s ok.
If you want your coffee to be hotter while drinking it, check at the bottom. There is a method there to keep it as hot as possible before you start drinking.
How to get the right temperature
If the temperature is such a big deal, how can you make sure you get the water at the right temperature? There are two ways to do it. One is much more practical than the other although not as accurate.
Want to do it in an absolutely scientific way and get your coffee perfectly consistent and perfect? Get a kitchen thermometer. If you’ve got one for meat, that will work, just clean it very well before use.
This way you get the correct temperature every time. This will lead to the most consistent and best results.
However, you and I both know that there are not many people that are going to do this, especially if you’re just making coffee for yourself, so what’s the shortcut?
Wait a minute
Yeah, literally. Just wait a minute after the water boils . You’ll more than likely heat up your water in an electric kettle. These keep going until the water boils and then shut off. And we all know that water boils at 100 degrees C or 212F (Yeah, yeah, at sea level).
That means it’s much easier to let it cool down from a temperature that’s always the same for a period of time than letting it warm up for a certain period of time. There’s less room for error. Still, if you’re not going to measure there is a pretty big room for error.
So how long should you wait until the water has cooled down from boiling to 205 or 195 degrees? About 15 seconds for 205f/96c and 30 seconds should get you to 195f/90c. Although a lot depends on the kettle and ambient temperature. You might not get this right on the first try so don’t be afraid to experiment.
To get it perfectly right, of course you can also combine both methods. If you always use the same kettle, the period you have to wait will always be very similar. That means you only have to use the thermometer once and you can just wait the same amount of time every time after that.
Just get your water to a boil, stick the thermometer in and set a stopwatch to see how long it takes to get to the right temperature. Then just wait that amount of time the next time you make coffee.
A bit geeky? Sure, but you want good coffee right?
What happens if the water is too hot?
What is the problem with water that’s too hot?
Think of it as doing laundry. The hotter the water is, the easier all the stains and smell are to get out of your clothes, but at the same time the hotter temperature can damage the colors and structure of the fabric. Some fabrics can handle hot washing better than others. Something similar is going on with coffee. You’re kind of ‘washing’ the taste out of it with hotter water.
So, continuing that comparison, some coffees can handle more heat before the brew starts tasting bad the same way some fabrics can be washed hotter without problems. Or maybe better said, there is less dirt in the coffee which you don’t want in your cup.
The biggest problem for most coffees is that it becomes too acidic if brewed too hot. Some acidity isn’t a bad thing but if it’s overpowering, the taste becomes unpleasant.
While there are more about 30 types of acids in coffee beans, there are two acids that are mainly responsible for this sour taste: quinic acid and chlorogenic acid.
These two get released more with heat. That means more heat causes a more sour taste. These also keep developing after the extraction process if heat keeps being applied. That’s why coffee that’s kept hot doesn’t taste good.
So, simply said, if the water is too hot, the taste isn’t as good as it could be or even unpleasant.
What happens if the water is too cold?
While too hot isn’t great, too cold isn’t the best idea either. Unlike cold brew, most brewing methods rely on the heat in the water to extract everything from the coffee grounds.
That has as a result that the coffee tastes weak. It might also lack caffeine although that’s not a drawback for some. Caffeine tends to extract a bit easier than many other things in the coffee beans because it’s water soluble.
My coffee is cold!
Maybe you like your coffee scolding hot. The temperature where the metal spoon in the coffee almost starts melting. If you make coffee in a Phin, it probably isn’t going to be to your liking. For most people who drink Vietnamese coffee this isn’t a problem since they add ice anyways. But for those who like it hot, there is a solution.
If you get the water at the right temperature, it might be too cold for some. Putting hotter water in the filter isn’t the right solution, but it’s actually pretty easy to remedy. You just need an extra bowl and some water.
Instead of putting your cup on a coaster, put your cup in a bowl and then on a coaster. Then put hot water in the bowl. This will keep the coffee hot for longer because the more liquid you have, the longer it takes to cool down. Also, you start with a hot glass which helps quite a bit.
If you want the absolute hottest possible Vietnamese coffee, you can add some boiling water to the bowl at the end of the brewing process.
The only drawback is that the cup will be wet on the outside so it’s a good idea to have a little towel nearby.
Favorite Vietnamese Coffee Products
To make Vietnamese coffee you don’t need many things so makes sure the things you use are correct!
Vietnamese Coffee: Get your traditional coffee from Nguyen coffee supply. It’s freshly roasted in the USA so it’s much fresher than imported bags. The used beans are 100% Vietnamese. Here’s a combo pack (Amazon) to see what you like best.
Phin: The only way to brew Vietnamese coffee is with a Phin. This one (amazon link) works well is cheap and reusable.
Scale: Even though a Phin isn’t super picky with weights, to brew and adjust your cups to be consistently delicious, a simple scale helps tremendously. I’ve been using this one (Amazon link) for over a year and while it’s not the most aesthetic, it works well.
Condensed milk: To make the delicious ca phe sua da, you need condensed milk. This one (Amazon link) is organic and works perfectly.