Friday, May 14, 2010

Is Your Coffee Fresh? The Coffee Bloom Test by Cleo Coyle

So there you are, sitting at your restaurant table. You've had a delightful meal. The ingredients in your entrée were fresh, the flowers on your table are fresh (the waiter might even be fresh), but what about the coffee he brings you?


You walk into a take-out place and the counter person hands you a paper cup of joe. Was the coffee made fresh? Or has it been sitting around since the Carter Administration?

Let me be clear about this: As a paying customer, you deserve a fresh cup of coffee -- every time. You can certainly tell if coffee is stale by sipping it, but if you want to spare your taste buds the pain of stale brew, here's a visual way of telling...

Cleo Coyle's
Coffee Bloom Test

When coffee is fresh, cream or milk poured into the cup will "bloom" to the top very quickly and remain at the top of the cup without dissipating much. A small amount of cream or milk will turn the coffee a palatable shade of nut brown.

Click the arrow below to watch half-and-half ("half cream")
added to a cup of fresh drip-brewed coffee.

Watch for the very fast "bloom" of the cream.

As coffee ages, oils in the beverage float to the top. These oils create a filmy barrier, so when you pour in the cream, the bloom is no longer instant. It will take silightly longer to surface, and when that cream rises to the top of your cup, the oily film will break up the pretty bloom, pushing it back down and dissipating it into murky swirls in the process.

In addtion, the same amount of cream that you used in a fresh cup will not lighten the beverage to the same palatable shade. (You'll find yourself pouring more and more milk or cream into the cup just to get it to same shade of lightness that you're used to getting in a fresh cup.)


Click the arrow below to watch half-and-half ("half cream")
added to a cup of drip-brewed coffee that's been on the burner
for 30 minutes.
Note the bloom takes longer to reach the top
and the oils on the top surface break up the bloom,
pusing it back down and making the mixture murkier...

If a restaurant, café, or fast food chain serves you a cup of coffee
that is not fresh, hand it back and politely ask for a freshly made cup.
Just tell them Cleo told you to do it :-)

A good bartender shouldn't be handing you a flat beer, right?
And a self-respecting chef wouldn't serve you a salad with rotting tomatoes.
Fresh coffee is your right as a consumer.
And anyone in the food service business would and should agree.

Click below to see a faster replay.
Fresh vs. 30 Minutes Old

Now let's look at
the freeze frames...

To the left is fresh coffee, ten seconds after cream has been poured in.

To the right is old coffee, ten seconds after cream has been added.

As you can see, the oils in the coffee to the right have created a filmy barrier, which is fighting the cream's ability to lighten the top surface of the coffee. A good barista or restaurateur would never want you to be served coffee like this. Politely ask for a fresh cup and...

~ Cleo Coyle, author of 

To get more of my recipes,
enter to win free coffee, or
learn about my books,
including my bestselling
Haunted Bookshop series,
visit my online coffeehouse:

The Coffeehouse Mysteries are national bestselling
culinary mysteries set in a landmark Greenwich Village 
coffeehouse, and each of the ten titles includes the 
added bonus of recipes. 


The Ghost and
Mrs. McClure

Book #1 of 

The Haunted Bookshop
, which Cleo writes
under the name Alice Kimberly
To learn more, click here.


  1. I *always* wonder if the coffee has been sitting on the hot plate all day! Now I'll know. And I'll be sure to tell them Cleo said they need to make a fresh pot for me. :) The one on the right definitely has a marbled look to it.

    Mystery Writing is Murder

  2. Great test Cleo. A quick and simple way to know.

    Thoughts in Progress

  3. What a fun test! One other thing to consider is the freshness of the half and half. At places like Starbucks that generally isn't a problem because the cream is kept in a thermal carafe and is poured fresh every so often. But at a neighborhood diner where the little half-and-half creamers have been sitting on the table (unrefrigerated) all morning... ugh.

    I love seeing the clouds in my coffee (ha - now I'll have that song in my head all day!), and I never stir because I enjoy watching those happy little bursts in my mug.

    Thanks for the fun post, Cleo.


  4. Replies to --

    @Elizabeth - LOL! I know how hard people work in the food service biz, and I'm sure they hear complaints every day. But I also know that good people in that biz want their customers to have good experiences in their establishments. Nothing wrong at all with politely letting a server know that the coffee he poured is not fresh. (Can you tell I'm obsessed with the bean :-)

    @ Mason - thank you and thanks for dropping by!

    ~ Cleo

  5. Reply to --

    @ Julie - Excellent point about the half-and-half (or "half cream" as they say in the UK). What customers should watch for on that one is a silight curdling of the cream or milk in their cup (little flecks of white appearing instead of a smooth blending of liquids).

    If that happens (right you are!) you may have a fresh cup of joe but a bad cup of cream. Just ask for new coffee and new cream, too.

    Grinning because your great comment reminded me of a girlfriend I had in college who liked to *drink* the half-and-half straight from the little plastic cups. We'd sit down at a diner and she'd start shooting half-and-half like shots of whiskey. Really embarrassing! Have not seen her in years, but I hope she's stopped by now! LOL!


  6. Reply to --

    @ Juju - Thank you - and thanks for dropping by the virtual *kitchen* - have a java joyous weekend and may your coffee always be fresh :)

    ~ Cleo
    Cleo Coyle on Twitter

  7. I had no idea! I will never be able to order a cup of coffee again -- without testing it. Great post, Cleo!

  8. Reply to --

    @ Jenn - It's actually a fun test. I love watching for that bloom...and guessing just how fresh (or not) my coffee is!

    Cleo Coyle on Twitter

  9. Very interesting, Cleo! Thanks for sharing.

    ~ Krista

  10. This is genius! As a bit of a food science nerd (I'm no expert but I think it's fascinating) I just love this. Thanks for the tip!!