Higher Grounds

Question

Carl from Louisiana

I recently purchased a BUNN Home Brewer from my local Wal-Mart. Very pleased with the excellent coffee flavor that this brewer develops. I use about 2.5 oz of coffee to brew a 10 cup pot. I was using 100% whole bean coffee at first but the brew basket would overflow. I now use about 60% whole bean and then put about 40% pre ground coffee on top. At that ratio I find the brew basket does not overflow. I clean the brew basket regularly along with the spray head. Any ideas on how I could use 100% whole bean and not overflow the basket.

Not really wanting to cut back on the 2.5 oz measurement which by SCAA Gold Cup standards should not be to much. Looking forward to hearing from you.

Carl

Answer

Carl,

The issue you are experiencing may be that your coffee has not degassed long enough. You mention blending a portion of coffee that was previously ground and has likely released a portion of the carbon dioxide from inside the beans. I suggest checking the grind particle size and possibly grinding slightly coarser. Another choice would be to try an optional spray head to lengthen the water delivery time. This would allow the brew water to penetrate the ground coffee and release the extractable material you want, at the same time reducing the float of the coffee in the filter.

Happy Brewing,

Dr. Brew

Clear Picture

Question

Dr. Brew, what causes an oily film to appear after brewing coffee, is this caused by the mineral or lack of mineral????

Walter Henry

Answer

Walter from Little Rock,

The oil film on the surface of brewed coffee is a natural occurrence. Certainly the quality and temperature of brew water can effect the amount of oil that is present. Brew water temperature above 205°F/ 96°C can extract more oil from the ground coffee. The most likely contributor to the oil is the degree of roast development. Many dark roasts (French / Italian roast) have oil drawn to the surface of the bean during roasting. Coffee oils also migrate to the surface of roasted beans as they release the carbon dioxide inside the bean during storage.

Happy Brewing,

Dr. Brew

Decaffeinated Coffee

Question

Dr. Brew:
What is there about decaf coffee that sometimes cause us so much trouble with the way water is adsorbed?
Jerry

Answer

Jerry,
Brewing deaffeinated coffees has been a challenge for a lot of coffee preparers.
I'll be the first to tell you I don't have the knowledge of all the effects of the decaffeination processes. When coffee beans are roasted for non-decaffeinated beverage the beans were processed primarilly to remove the wet (washed process) or dried (natural process) mucliege from the seeds/beans. When beans are processed for decaffeination they are saturated in water, chemicals or carbon dioxied. Through all of these processes to remove caffeine, additional bean solubles are removed including waxes and oils. Decaffeinated beans do not expand as far in the roasting process. This can lead to lower extraction rates due to smaller internal openings in the roast and ground coffee. As water is applied to the ground coffee the reaction of absorption and release of the extractable material from the decaffeinated coffee is altered compared to regular ground coffee. Decaffeinated coffee will generally take longer to brew, due to how the coffee absorbs and holds water during the brewing cycle. Contact your roaster/ coffee provider to learn more about the options they have for decaffeinated products. http://www.coffeeresearch.org/science/decaffeination.htm

Happy Brewing,

Dr. Brew

Mystery

Question

From Mike

Dear Dr. Brew,
The one nagging question that no one has ever definitively answered: why a "cup" of coffee is 5 ounces.

My theory has been that's what grandma's china tea cups hold.

Is there another answer?

Thanks,

Mike

Answer

Serving size has always been a marketing mystery to me as well. As I learned to cook, a cup by volume was 8 fluid ounces. It's likely a cup at home held 8 ounces and was filled with 6 ounces for room to add cream and sugar. During my 30 plus years involved with beverage equipment and preparation I have heard the serving size/volume at both 5 and 6 ounces (never 8). My educated guess is that the number comes from a division of the final liquid yield of beverage.

As an example: If 68 ounces of water were dispensed over 4 ounces of ground coffee, the finished yield of brewed beverage (one ounce of coffee absorbs approximately two ounces of water) would be approximately 60 ounces. This is easily divided as 5 -12 ounce servings, 6 -10 ounce servings, 10 - 6 ounce servings, or 12 - 5 ounce servings to determine a cost per serving.

And Grandmother's tea cup started it all.

Happy Brewing,

Dr. Brew