You will often hear that filter coffee should be brewed with water "just off the boil". What does this really mean? Is it even a useful tip?
(Note: this post only applies to filter coffee in all it's forms, not espresso)
The idea that boiling water burns coffee has been going round for years now, but I don't think it has much truth to it. Our coffees are subjected to temperatures over 200°C. If anything was to burn the coffee, it'd be this.
Water temperature does play a key role in coffee brewing. Essentially, the hotter your water, the more you will extract from your coffee. If you have a supermarket dark roasted coffee, you will extract a lot from the coffee. This will include all the 'burnt', 'roasty', 'ashy' and 'bitter' flavour compounds. In this instance, you may want to brew with water that is a little less hot (maybe 90°C-95°C).
We take great pride in carefully manipulating roast profiles. We always aim to have a final product that is balanced, tasty, and free of any defects. Using boiling water will generally only pull more delicious flavour into your cup. With some of our lighter roasts (like our new washed El Rubi from Colombia), you will definitely be wanting to use the hottest water possible).
It is also important to note the drop in temperature that happens in brewed coffee. Whether it be a cafetiere, a V60 or an aeropress, your brewer will always be losing heat to the outside environment. This means that even though you may be using 93°C water, by the time your brew is finishing, it may have dropped to lower than 85°C. This is another reason for using boiling water.
Just in case you needed another reason, Matt Perger of Barista Hustle says:
"you can't see the difference between 60°C and 94°C, but you can see the difference between 97°C and 100°C."
The fact that boiling water is so much easier to use can make our mornings a lot more enjoyable, because nobody wants to wait for their water to reach 94°C at 7:00am!
When to change your water temperature:
I would always advise using boiling water for the reasons already mentioned. However, if your coffee is tasting a little bit ashy, roasty or bitter and you have already adjusted your grind size, you may want to use a slightly lower temperature water. Start by leaving it for 1 minute in the kettle. This should drop it by a few degrees, but nothing too dramatic.
Another instance where you may want to use a lower temperature water is with a low quality coffee. If you are stuck with a supermarket old, dark roasted coffee then using a lower temperature water may help to hide some of the 'roast' flavours.
As with any variable in coffee brewing, play around with it, find what works for you, and have fun making the best cup you can!
I'd love to hear your experiences with water temperature, drop me a message on Instagram @moonroastcoffee !
Please leave a comment below if you have any questions.
If you want to explore the topic of temperature further, I have left these links to help you out.
https://www.youtube.com/watch?v=1B02U5ZqJhM (start at 6:50)