Food or edible material: processes – compositions – and products – Processes – Extraction utilizing liquid as extracting medium
Reexamination Certificate
1999-06-07
2001-05-08
Weier, Anthony J. (Department: 1761)
Food or edible material: processes, compositions, and products
Processes
Extraction utilizing liquid as extracting medium
C426S594000
Reexamination Certificate
active
06228410
ABSTRACT:
BACKGROUND OF THE INVENTION
Coffee is a beverage that has a taste and aroma which is more desirable when it is fresh than when it is older and “stale.” This is because the compounds which contribute flavor to the coffee are organic in nature and the flavor is the most desirable immediately after the coffee is brewed because the compounds which impart the flavor have not degraded. Over a period of time the organic compounds of the coffee oxidize by combining with oxygen in the water from which the coffee is brewed and the oxidation results in the degradation of the coffee and the loss of the desirable flavor.
There are numerous brands and types of coffees available, and coffee can be brewed such that it is “strong ” or “weak ” or to any intermediate strength. Individuals who regularly drink coffee desire that the brew have a “strength ” and level of “freshness ” which is satisfactory to their own palate, and therefore the strength and the freshness of coffee are critical variables to connoisseurs of coffee.
One who makes a pot of coffee may grind or purchase his choices of coffee grinds and place those grinds within the hopper of a coffee maker. Hot water is either percolated through the grinds or it may flow from a reservoir above the hopper through the grinds to a removable coffeepot below the hopper. The degradation of the coffee commences as the pot is filling with coffee and proceeds at a rate that may vary depending on the type of coffee and the degree of the grinding.
In our previous U.S. Pat. No. 5,724,882, we disclosed a coffee maker having an optical feedback system in which a red light from an LED was directed through a transparent coffee pot and the intensity of the light passing through the liquid was monitored to make a brew having a predetermined concentration. U.S. Pat. No. 5,724,882, therefore, disclosed a method and apparatus for brewing coffee to a predetermined strength. Coffee from a coffee maker in accordance with our prior invention will nonetheless become stale over time, and a connoisseur of coffee employing such a coffee maker could not ascertain whether the coffee has become too stale for his palate without tasting it. It would be desirable, therefore, to provide a coffee maker which would brew coffee at a desirable concentration or strength and which would also provide a readout of the freshness of the brew remaining in the pot.
SUMMARY OF THE INVENTION
Briefly, the present invention is embodied in a coffee maker having a hopper for retaining coffee grinds from which coffee would be brewed and having a heating element below the hopper having a generally planar upper surface for receiving a coffeepot. The coffee maker further includes a source of hot water, which may be a heated reservoir positioned above the hopper and a control valve for controlling the flow of hot water from the reservoir through the coffee grinds and into the pot on the heating element below.
In accordance with the invention, the pot is transparent and the device further includes a light source or LED for providing a beam of light having wavelengths in the ultra violet, visible, or near infrared range which is directed through the lower portion of the coffee pot to a photodetector on the opposite side of the coffee pot. The device further includes a circuit for measuring the intensity of light detected by the photodetector by measuring the voltage output of the photodetector to determine the transmittance of light through the coffee.
We have found that the organic components which make up fresh coffee are partially transparent to light waves, especially to red light waves from an LED, but as the organic matter which imparts flavor to the coffee degrades and the coffee brew becomes progressively more stale, the transparency of the brew to the light also progressively decreases. We have found that the voltage output of the photo detector drops at a rate which corresponds to the rate at which the coffee looses its freshness and becomes stale and therefore a display of the downward progression of the voltages from the photo detector is also a display of the deterioration of the freshness of the coffee.
In accordance with the invention, the circuitry of the device includes a means for digitally measuring the voltage potential of the LED and storing that voltage in a first register. Subsequent voltage measures are thereafter compared to the first voltage in a first comparator and if the new voltage is larger than the old, replacing the old voltage with the new until a maximum voltage is found. In like manner a second register and a second comparator are used to find a minimum voltage output from the photodetector. The maximum voltage is reached when the coffee has the greatest transmittance to light which occurs at the completion of the brewing of the coffee. The richest coffee having the lowest transmittance is made with the water which first passes through the grinds in the hopper and therefore the first reading from the photodetector, when the level of coffee in the pot is the lowest level covering the photodetector, is taken as a minimum voltage output.
The circuit causes the maximum voltage, as recorded in the first register, to be a measure of maximum freshness and the minimum voltage as recorded in the second register to be a measure of minimum freshness or stale coffee. After the brewing of a pot of coffee is complete, the organic matters which impart flavor to the coffee gradually oxidize and the brew becomes less transparent to light. As this occurs, the voltage output of the photodetector drops from the maximum, as recorded in the first register, toward the minimum as recorded in the second register. As the voltage output falls towards the minimum, the brew is becoming stale. A LED bar graph may be employed as a display of freshness in which all ten LED 's are illuminated when the coffee is “fresh ” and progressively fewer LED 's are illuminated as the coffee becomes progressively more “stale.”As explained in our patent U.S. Pat. No. 5,724,882, we have previously found that the transmittance of light through the organic compounds which impart flavor to fresh brewed coffee is at a maximum in the range between 600 nm and 1,400 nm. Fresh coffee is partially transparent to light within this range with the absorption of light being directly proportional to the amount of organic matter which imparts flavor to the coffee. Degradation of the organic matter will result in decreased transmittance of light through the coffee within this wavelength range.
We have also found that the freshness of fresh brewed coffee can be extended by adding an antioxidant to the coffee grinds or to the water in the reservoir. This may be accomplished in any of a number of ways including depositing an antioxidant within, or on the surface of, a filter used to retain coffee grinds in a hopper.
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Gallas James M.
Panosh Richard
Zajac Gerry W.
Marsh Robert L.
Weier Anthony J.
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