I’ve been experimenting with my v60, EK43, refractometer and variable temperature kettle. I understand somewhat how grind size, water-to-Coffee ratio, agitation etc. affect extraction, but I am unclear on the role water temperature plays. I’ve heard 195-205 F is ideal slurry temperature, but how do I know when I might need to make a change in water temperature?

  • I'm afraid I didn't get the question. You can use a thermometer to measure the temperature?
    – MTSan
    Dec 30 '18 at 16:07
  • What factors indicate a change in water temperature might be necessary? How do I know I need to set kettle to 205 instead of 203? What factors indicate to turn the temperature lower? What factors indicate to turn temperature higher? Dec 30 '18 at 17:00
  • I see. Temperature simply has a positive effect to extraction. Keep the temperature warmer to decrease the time to extract.
    – MTSan
    Dec 30 '18 at 18:30
  • I’ve heard it can also degrade acids, changing their properties in a way that undesirably flavors the coffee differently. I was hoping someone here would be able to tell me how to detect when that’s happening. Dec 30 '18 at 19:26
  • If the taste comes out bitter, try again with cooler water or coarser grind. If it comes out sour, try hotter water or finer grind. There are questions on that topic with more extensive answerers, but at the moment I can't think of the query terms to use. There are charts with refractometer info but I haven't tried that.
    – Jerry101
    Dec 31 '18 at 4:03

Agreed with the above answer by Jason: it's about taste.

That said, of late i have been surprised by how effective for extractin Scott Rao's 97degree C is for a pour over[link].In particular it seems that central and south american beans need the temp to get out the flavour - african's less so but still work in that range.

But to your question - a more specific mapping of flavours:

Matt Perger has a super chart to map when temp may come into play based on what you're tasting and how to tweak it. (2)

  • Always appreciate beacons of truth such as the names Rao and Perger. Is your posting this connected to my post on Barista Hustle FB group? Feb 2 '19 at 23:30
  • Jonathan - sorry no - the post was simply a reply / answer to the original question - perhaps i've done something wrong? new here; - don't use Facebook
    – m.c. von s
    Feb 3 '19 at 17:15
  • Haha no you just posted your response the same day I posted about stack exchange coffee site in the barista hustle group. Sorry for the confusion! Feb 3 '19 at 19:17

The best way to detect what's happening is with your tongue. Try doing two batches brewed all the same minus temperature. Start out at 190 vs 210 and close in until you can't tell a difference. Use various palate cleansers (like cereal or eggs and switch between sweet/salty/sour foods to really get a picture of what's different between the two batches). Taste the coffees at various temperatures, sometimes coffee can get sweeter when it's cooler. Try out the coffee cupping tasting slurp method.

Refractometer might tell you a gravity reading, but it doesn't tell you anything about flavor or mouthfeel. Finally go with what tastes the best, and realize that for any particular grind size, brewing method, and coffee combination, the perfect temperature of your water will vary.

Happy brewing!

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.