I have been curious about the topic of acidity lately. I've went to a couple cafes over the past few months and found some of the non-espresso coffees to be a little too acidic for my tastes. Usually when I roast at home for french press or pour over, I have found that I like a roast level that is mildly acidic when hot but then becomes a little more acidic as it cools. This is in contrast to something that starts off highly acidic and then becomes almost unpleasant as it cools. I do admit that I tend to drink a cup of coffee rather slowly so a single cup usually will go through a healthy degree of temp change, but I find I like the changing experience I get in a single cup of coffee. Anyhoo, I guess this is one more reason to roast at home. You get to roast it how you like it. Anyone have a different take on the subject? Do roasters expect consumers to drink their coffees while they are quite hot, before any change occurs, or do they assume the consumer will be drinking the coffee as it cools and becomes more acidic?

M

Roast flavors become less pronounced as the coffee cools, so the acidity becomes more noticeable, rather than stronger. A high quality coffee will be well balanced between sweetness and acidity, like a good white wine, and should taste anywhere from sweet to dry, but never sour. Many importers and roasters select coffees based on how clean, crisp and balanced they taste when cool.

Acidity (brightness) is considered a desirable flavour characteristic in high quality coffees.

Roasters (or good roasters at least) cup their coffees as they cool (at least at three different temps).

Remember that acidity is different than acidic.

malachi wrote:Remember that acidity is different than acidic

Chris -can you explain this thought?

I take acidity as a phrase to imply a quantitative measure of a solution (ie. its pH measurement below 7)

I take acidic as a word implying a solution has a pH below 7 (its acidic)

Is there another way to read this?

Thanks

Coffee Definitions of Acidity (sometimes called Bright or Acidy as well)...

ICO - "A desirable sharp and pleasing taste particularly strong with certain origins as opposed to an over-fermented sour taste."
Sivetz - "A desirable flavor in high grown coffee - sharp and pleasant but not biting."
Nestle - "A normal characteristic of arabica coffees, particularly of high grown varieties. Some strains are sought for this particular taste, which is influenced by the degree of roasting and does not seem to be objectively measured by a pH measurement."
Lingle - "A primary coffee taste sensation related to the presence of sweet tasting compounds. Created as the acids in the coffee combine with the sugars to increase perceived overall sweetness. Found most often in washed arabica grown at elevation above 4k feet. Range in taste from 'piquant' to 'nippy' with the taste sensation experienced in the tip of the tongue."
CBC - "Sharp and pleasing to the taste as opposed to sour or sourish or fermented. It denotes a taste that has sharpness, snap and life as compared to a heavy mellow flavor. Old crop coffees never have this flavor."

There is no relation between tasters' acidity, a quality measure, and pH, a quantity measure. At least this is true using conventional methods for measuring pH; Vitzthum and Clarke suggest that tasters' acidity may be correlated to the pH as measured by titration with an alkali. This would suggest that the effective acidity in coffee is buffered by other electrolytes, i.e. that its effect on reagents like those your taste buds interacts strongly with the sugars.

This is why all of the definitions Chris quotes emphasize the relation of high quality acidity with sweetness. Coffees that taste very acidic but not sweet are usually fermented, harsh, or unripe.

Excellent description (far better than mine).

Many thanks gentleman.

I've learned somthing useful today.