Here’s a great question about coffee temperature and brewing coffee with a hand drip coffee maker from one of our subscribers to our Coffee Tasting Course.

Sun Min asks …

Hi Mark,Thanks for responding to me so kindly.  I am glad to know that your  e-Course is on the way.

I have one question for you regarding the water temperature when you brew the coffee either using French Press or any other hand drip methods.  I read in several places that the temp. of water should be just off of a boil (around 195-205).  My question to you is I recently bought a cute Vietnamese hand drip coffee maker, but it takes at least 5 minutes to extract a cup of coffee, so by the time the coffee is made, the coffee tends to be not that hot.  I happen to love really hot coffee.  Why shouldn’t I use boiling hot water?  Is there any scientific reason to that?  Please let me know when you have some time.
I hope my question makes sense to you.

Thank you very much for your help.

Sun Min

Sun Min, thanks so much for this coffee brewing question.  Interesting problem, and I think I may have a few ideas for you.

First, let me say that a hand drip or pour over drip coffee brewing method is one of my favorite ways to enjoy a good cup.  The method is simple, and maybe even seems too low tech for some.  But with all the technology that has infiltrated the coffee culture, it’s still hard to beat the simple but effective hand drip brewing technique.  And it’s easy on the pocket book too!

So let’s restate the problem you’re running into.  The brewing time is taking over 5 minutes, which leaves you with a cup of coffee that has cooled down in temperature considerably.

Let’s start with your question about water temperature.  Yes, achieving a proper extraction does depend on getting the water temperature right.  The ideal range is between 195 deg Fahrenheit at the low end and about 204 degrees at the top end.  Water hotter than 204 degrees will tend to cause over-extraction which results in a more bitter taste coming through.  And water cooler than 195 degrees will usually require more infusion time to get the full extraction to occur, which means the brewing time when the water is in contact with coffee grinds needs to be extended.

In your case, I’m certain that even if you started with hotter water (and you can’t get any hotter than 212 degrees F at boiling temperature), you’ll still wind up with considerably cooler coffee in the cup because of the longer 5 minute brewing time.

With a French Press, the 3 to 5 minute brewing time works fine because the insulating aspect of the glass beaker tends to keep the coffee temperature from dropping too much.

So what can we do about the hand drip brewer?  Brewing coffee is a combination and balance of several key factors; water temperature, infusion time, the amount of coffee grinds, and the size of the coffee grains (coarse or fine).

To prevent the temperature of the coffee from dropping as much, one approach is to reduce the brewing time.  Now, without seeing your “Vietnamese Hand Drip Coffee Maker” (sounds wonderful by the way), there could be a design challenge that causes the water to back up and flow too slowly through the coffee grains.  But more likely, you might want to look at the level of your coffee grind for a solution.

And this is why I’ve taken the opportunity to write in detail about your question.  Grinding coffee, and the coffee grind level is easily one of the most miss understood principles of good coffee brewing results.  And adjusting the grind level (coarse to fine) is one of the most effective ways to effect the brewing result.  And this goes for espresso coffee as well.  Which is why you will frequently hear … “it’s all in the grind”.

Let me refer you to an article on our web site, “Coffee Grinding Physics“. Yikes, sounds complicated, but it’s not hard to understand.  I won’t restate the principles of coffee infusion and grind level here, but let’s net it out.  You may be grinding your coffee too fine for the hand drip brewer.  With a coarser grind, the water will drip through faster with less time for the temperature to drop off.  The key and balance that you’re after is to strike the better grind level (a little more coarse) and still achieve a full extraction result.

So, how do you adjust the grind level?

That’s where a little bit of technology helps.  You can consider a quality burr grinder that enables a more precise adjustment from coarse to fine.  Typically, a burr grinder literally lets you dial in the grind level.  Ah, but these grinders are pretty expensive.  We recommend the Maestro Baratza Conical Burr Grinder as a great entry level burr grinder at just under $100 US.

For all of our gourmet coffee aficionados,  there probably is a burr grinder in your future.  But I completely understand, these are more expensive devices, so what to do if you’re watching the budget?

I’ll assume you’re probably using a blade or spin grinder today.  As the coffee grinding physics article points out, a burr grinder enables more precise grind level control as well as consistency of particle size, but we can still manage to work with a blade grinder.

With your blade grinder, simply grind for a little less time, so you don’t break the particles up as fine.  Or try pulsing the grinder rather than a constant spin to achieve a more coarse grind level.  The key is to experiment.  Try to hit a coarser grind, and then brew a cup in your hand drip brewer, and watch for a faster drip.  See if you can get to 3 minutes down from 5 minutes.  Then taste the coffee, and see if it achieves the strength, body and fullness you’re after.  If you get the grind level too coarse, you’ll speed up the drip time, but you will likely end up with a weak brew.

Another option is to have your favorite coffee store grind the beans for you.  I know, we always preach that “you should grind your own beans” for freshness, but a good coffee store should have a high end, quality burr grinder that can get the job done right.  Tell them what you’re after, a somewhat coarser grind for a hand drip or pour over drip brewer.

Better yet, if you can locate the right specialty coffee store in your area, bring your Vietnamese brewer in with you, and ask them if they could help you achieve a better grind level.  Setup a time when they’re not busy, buy a pound of coffee beans of your favorite choosing from them, and then ask them to prepare several doses of ground coffee at different grind levels for you.  Then experiment right there in the store.  If you approach it right, you’ll make a friend for life out of the barista at the store, and they will welcome the opportunity to help an interested customer if they share the coffee passion.  You’ve gotta find the right place, though.

As I mentioned, the other factor that you want to pay attention to, is the amount of coffee you’re brewing with.  You might try a little less coffee in the hand drip brewer.  This will also speed up drip time.  Again, too little coffee will result in a weaker cup.  But often, using too much coffee doesn’t actually achieve a stronger brew beyond a certain threshold, because the brewer doesn’t necessarily enable enough infusion surface area to increase the level of extraction (sorry, that sounds too complicated).

Now, keep this in mind.  If you make the grind level more coarse, and you end up with a weaker brew than you desire, but you speed up the drip time and get the temperature in the cup that you’re after, you can try adding a larger dose of more coarsely ground coffee to the brewer to strengthen the extraction (fuller body, stronger coffee in the cup), but still maintain the brew time and keep the temperature from falling off.  In other words, at a coarser grind level, you may be able to offset the slightly weaker extraction, by adding more coffee to the brewer, and still maintain the faster drip time, and therefore reducing the temperature falloff. Wow, that was a mouthful.

But hopefully, you’re getting the idea.  You can adjust the grind level, and the amount of coffee to hit the brew balance that you’re after. A skilled barista works with all of these factors and variables to achieve the best brewing results, regardless of the brewing method; pour over/hand drip, a siphon brewer, French press, and of course, espresso.

I should probably also mention, if you want to take the easy way out, you can always zap your cup in the microwave and heat the coffee back up after brewing, but that’s cheating a bit 😉  Let’s see if we can’t help you get the result you’re after without having to resort to the microwave.

Anyway, that’s a lot to think about.  Try experimenting with a combination of slightly coarser grind levels and a little less or a little more coffee and see if you can speed up the drip time, keep the temperature from falling off as much, and maintain the strength of brew that you desire.

Sun Min, let me know how this works out.  I’m sure we can get your hand drip coffee brewer working great for you.

Mark