Name ________________________________________ Date ___________________ Period __________ THE SCOVILLE SCALE AND SERIAL DILUTIONS The Scoville scale is named after Wilbur Scoville, who devised it in 1912 as a way to rate the capsaicin content of hot peppers. The general protocol calls for an extract of the pepper to be produced using alcohol, and then diluted until the hotness can no longer be tasted by a panel of tasters. The number of times that a solution must be diluted is equal to the number of scoville units that a pepper is given. So a habanero pepper, rated at 200,000 scoville units, must be diluted 200,000 times before it can no longer be tasted. Your goal today is to use a modified and more modern form of this protocol to extract, dilute and taste several samples of peppers. PART I – CREATE YOUR EXTRACT WARNING! WEAR GLOVES WHEN DEALING WITH HOT PEPPERS! Obtain a pepper sample, and remove the stem. Coarsely chop the pepper and measure out 25 g of the pepper, seeds and all. Place the pepper and 200 mL of tap water into a food processor, and pulse until the consistency is smooth. Let the extract stand for 10 minutes at room temperature. Pour the extract through a coffee filter to remove any larger pieces of pepper. PART II – DILUTE YOUR EXTRACT The filtered results from part I represent the undiluted pepper solution. You are going to dilute the samples by a factor of five in each of the dilutions. From your original 200 mL sample, remove 40 mL. Place this 40 mL aliquot into 160 mL of fresh tap water. This sample is now 1/5 the strength of your original sample. Repeat step 3 until you can no longer taste the hotness of the pepper. Be sure to keep track of how many times you diluted the extract. To figure out how many times you diluted the pepper in total, raise 5 to the number of times that you diluted your extract. As an example, if you diluted your extract three times, raise 5 to the third power, or 53, and you get 125 times, or a scoville rating of 125.