Frequently Asked Questions

Here are some common questions or issues you might have.

Q: What should my coffee grind size be?

A: Tetsu Kasuya recommends a coarse grind, similar to French Press. However, it ultimately should come down to taste. Does your cup taste bitter and dry or empty? You’ve over-extracted – grind coarser. Taste sour or bland and watery? You’ve under-extracted – grind finer.

Q: What temperature should the water be?

A: It depends on how finicky you want to be. Ideally, it is recommended that your water temperature fit roast level of your coffee. Light roasts can use hotter water – between right off boil and 94ºC. Dark roasts work better with lower temperature water – as low as 80ºC. Medium roast is in between – around 91ºC. If you don’t have a kettle that you can set the temperature to, or don’t have a kitchen thermometer to use, just boil your water and let it cool for 30s or up to a couple minutes, and you’ll be in the ballpark.

Q: How fast should I be pouring the water? Can you update the app to show the water amount go up so I have an idea?

A: There really isn’t a set rule on this, which would make adding such a guide to the timer a little difficult. In videos of Tetsu demonstrating his technique, his pour ranged from 8 seconds for his first pour (50g) down to nearly 3 seconds for his last (60g). So a blanket answer may be to average about 5 seconds for each pour, but also that precision timing is not required for successfully using this method. So try to not stress about it. Your times could vary as well based on how much water your particular recipe calls for.

Q: The flavor of my coffee is bad. How do I fix it?

A: How does it taste bad? There is a general rule of thumb that you can follow that may be enough to fix it. Does it taste sour or bland? Grind finer. Does it taste bitter, astringent, and empty? Grind coarser.

Troubleshooting coffee extraction can be tricky though. For example, what’s the difference between bland and empty? Knowing often comes with experience, but even then it may require some experimenting. If you’re trying to figure out what adjustments to make, it’s best to avoid changing multiple things at once or swinging widely from one end of the spectrum to the other. Grind size, grind uniformity, water quality, temperature, pour speed, water to coffee ratio, type of filters, type and variety of coffee, and the general quality of the beans and the roast are all factors that play a role in extraction. Change only one thing at a time to dial it in, and try to not make big changes at once. Often times, subtle changes can be enough. Generally, grind size is going to be the easiest way to dial in a particular coffee, and it may change from one type of coffee to the next. So never expect there to be a “one size fits all” solution to solving why you’re not enjoying the coffee you just brewed, or expect what worked for one type of coffee to work with another.

If you find you’re still having a hard time dialing it in by flavor because you can’t tell whether it’s sour or bitter, it might be because it’s a little of both. Some lower quality grinders will produce a very uneven grind with large boulders and an excessive amount of powdery fines at the same time, meaning the boulders will under-extract and the fines will over-extract, leading to a confusing taste. If you think this might be your issue, see if you can borrow a high quality grinder from a friend or ask your local roaster to grind part or all of your bag ahead of time. Although fresh ground coffee is always ideal, this may be enough for you to be able to tell your own grinder may not be up to the task. Consider upgrading, or if that isn’t feasible at the moment, searching for ways to mitigate uneven grinds, like using a sifter or the “paper towel” trick.

Q: I poured the right amount, and all the water drained out before even getting to the next step. What’s up with that?

A: Most likely, this is normal. If you follow Tetsu Kasuya’s method, he recommends that all the water drain out before moving to the next pour. It’s recommended that each pour be about 45 seconds apart, so try to time it accordingly. If all the water drains out a lot faster than that (more than 10 seconds for every pour), consider grinding your coffee finer or even pouring slower, especially if it tastes sour.

Q: I poured the right amount, but all the water didn’t drain out before the next step like it’s supposed to. What’s up with that?

A: Like the previous answer, each pour should drain entirely before starting the next. If yours doesn’t, try pouring faster or use a coarser grind, especially if the coffee tastes bitter or astringent.

Q: Can I use this app with something besides a V60? Like a Chemex? Or a Kalita Wave?

A: The 4:6 method was originally designed for the V60. However, pour over brewing is generally going to be similar no matter what device you use – manually pouring water that passes through coffee grounds with a filter. You may need to adjust some variables, but try it out and send your feedback.

Q: I did the math myself, and actually the pours don’t add up to the total water. It’s off by 1 gram.

A: This is an intended result. My goal for this app was to take a complicated process and simplify it as much as possible, while still producing great results. The intention is not to provide perfect, scientific precision and accuracy. The coffee and water amounts are always rounded to whole gram amounts. In my own years of experience brewing specialty coffee, a gram or 2 difference in water or coffee is not likely to make a big difference in your result. If I show the full decimal amounts, it may give the impression that precision is important, and consequently many users may stress out trying to get it exactly right. Instead, I want my app to be a relatively relaxing and simple experience. If you find that the math is actually off by more than a gram, you can reach out via email with the recipe you used and I’ll check out what’s going on.

Q: I have an issue or question not listed here.

A: Get in touch on Twitter – @FourSixCoffee. Or email me at