Unit and Recipe Conversions

1. Unit and Recipe Conversions • chapter 3

2. Opening Questions What is the difference between weight and volume? Are they interchangeable? Which tools measure weight and which measure volume?

3. Water Universal Water is interchangeable at • Because of this constant, you can convert between volume and weight on paper in intermediate steps as long as you return to the original type of measure (weight vs. volume) at the end. 1 pt= 1 # or 1 c = 8 oz

4. Table 3.1 • Review table 3.1 • Which measures are American/British? • Which are metric?

5. Table 3.2 and Figure 3.1 • These facts must be memorized in order to convert units • Practice daily until they become second nature • You cannot convert units without them!

6. Three Methods to Convert Units • You only have to learn one • Choose the one that makes the most sense to you Unit Size Operation Technique Left/Right Operation Technique Dimensional Analysis

7. Unit Size-Operation Technique Going from a larger size unit to a smaller one, multiply the number (to get more of those tiny units) Going from a smaller size unit to a larger one, divide (to get fewer of the big units)

8. Example 3a How many ounces are in 2 ¼ pounds? • Pounds (big) to ounces (small) • Unit down, number up = multiply • Ratio is 16 oz = 1#, so multiply by 16 • 2.25 # X 16 = 32 oz

9. Example 3b 8 cups equals how many gallons? • Cups (small) to gallons (big) • Unit up, number down = divide • Ratio is 16 c = 1 Gal • 8 c ÷ 16 = ½ Gal

10. Example 3c (requires intermediate steps) How many Kg of water are in 2 Gal? 1 Kg = 2.2 #, 1 pt = 1#, 1 Gal = 8 pt 2 Gal (big) to pt (small) = multiply 2 Gal X 8 = 16 pt 1 pt = 1 #, so 16 pt = 16 # 16 # (small) to Kg (big) = divide 16 # ÷ 2.2 = 7.27 Kg

11. Left/Right-Operation Technique Memorize in order • *Units with a “/” are equal to each other Large Small

12. Left/Right-Operation Technique Moving to the right (small to large) = divide Large Small Moving to the left (large to small) = multiply

13. Example 3d How many mL are in ¾ L? • Going from L to mL, move left to right = multiply • 1 L = 1000 mL • 0.75L X 1000 = 750 mL

14. Example 3e How many quarts are in 17 cups? • Going cups to quarts you move left to right = divide • 1 qt = 4 c • 17 c ÷ 4 = 4.25 or 4 ¼ qt

15. Example 3f(requires intermediate step) How many mL are in a 16 oz bottle of water? • 1000 mL = 1 L and 1 L = 33.8 oz • Move oz to L (left to right) = divide • 16 oz ÷ 33.8 = 0.47337 L • (don’t round on an intermediate step) • Move L to mL (right to left) = multiply • 0.47337 X 1000 = 473.37 or 473.4 mL

16. Dimensional Analysis • 1. Write the ratios as fractions • 2. Orient the fractions to the units cancel (each denominator’s unit is the same as the preceding numerator’s unit) • 3. Multiply the fractions • 4. Any units not canceled out remain in the answer in their same position (numerator or denominator)

17. Example 3g How many L does 2 ¾ pt represent? L = 33.8 oz and 1 pt = 16 oz 2.75 pt X X = 1.302 L or 1.3 L To compute, enter the starting number in a calculator. Then multiply by the numerators and divide by the denominators.

18. Example 3h How many cups are there in 2.35 gallons? • 1 Gal = 16 c 2.35 Gal 37.6 c = X

19. Why are Recipes Converted? • Chef may have a recipe using metric (or British) units but the kitchen tools only measure in the other system’s units • Chef has converted a recipe’s yield, and it is more practical to measure the ingredients in different units

20. How to Adjust a Recipe’s Yield STEP 1: You must know the original (old) yield and the desired (new) yield for the recipe. • Calculate a conversion factor (CF) CF =

21. Example 3i What is the conversion factor to change a recipe yielding 75 portions to one yielding 20 portions? • 0.266 or 0.27 CF = = =

22. Conversion Factor • If the portion size of the recipe changes, you must calculate the total weight (or volume) of each recipe’s yield before using the conversion factor formula. Total Yield = total portions X portion size

23. Example 3j Calculate CF to convert a recipe yielding 4 one-pound loaves of bread to one yielding 110 two-ounce rolls. • Old Yield = portions X size = 4 X 1 # = 4 # • New = 110 X 2 oz = 220 oz The units don’t match!!! Convert # to oz before proceeding 4 # X 16 = 64 oz

24. Example 3j (cont.) • The formula only works if the units for • new and old yield match. CF 3.4375 or 3.44 = = =

25. How to Adjust a Recipe’s Yield • New Ingredient Quantity = Old Ing. Q X CF • The biggest challenge is converting the unit to make the new ingredient quantity measurements practical in the real world. STEP 2: Multiply the conversion factor times each ingredient in the recipe to get a recipe that will produce the new yield.

26. Example 3k Convert the following recipe to serve 12 portions. Chicken Piccata Yield = 100 portions Chicken breast, boneless, 4 oz, pounded flat 100 ea Flour, all-purpose 2 ¼ # Butter 3 # Lemon juice 1 qt Chicken stock 2 ½ qt Capers, drained, 28 oz jar 1 jar Parsley, chopped fine 1 ½ c

27. Example 3k (cont.) • Multiply 0.12 X each ingredient’s quantity CF 0.12 = = =

28. Example 3k

29. Notes on 3k Solution • No unit conversion for “each.” • Rounding depends on measurement tools available. • Lemon juice and stock convert to oz only because they are mostly water. • Non-standard ratios (1 jar = 28 oz) are learned from labels or a kitchen test. • Choice of unit and how much to round can impact precision of the measurement.