Planning a Food Investigation

A fair test in the kitchen

A food investigation asks one question, such as what happens to a cake if you use less sugar. To answer it fairly you change one thing, measure one thing, and keep everything else the same. That matters in food more than almost anywhere, because ingredients work together. In a cake, creaming fat with sugar traps air, and egg and flour set around it. Change one ingredient and you can change what the others do, so anything you do not mean to change has to be held still. All of this is decided before anything is weighed. A good plan also keeps waste down and says how the results will be judged, often by tasting.

Words for planning an investigation

Five terms this module is built on.

Which variable is it?

A student tests how the amount of sugar affects a batch of muffins. Decide which kind of variable each one is. You have three lives.

Choosing a sensory test

Each test answers a different question. Samples are given codes rather than names, so tasters are not swayed by what they think they are eating.

Pick the tests

A student wants to know whether tasters can even tell a reduced-sugar biscuit from the standard one, and then to describe how its flavour and texture differ. Select the TWO tests that fit.

• A triangle test
• A star profile
• A paired preference test
• A ranking test

A plan for flaky pastry

A student wonders whether using butter or lard changes how flaky shortcrust pastry is. Before any cooking, the plan sets out the aim, then what is already known about fats in pastry, then a prediction: that one fat will give a flakier result, with a reason. The method names the type of fat as the one thing that changes, and flakiness as what is judged. The same weight of flour, the same rubbing-in time and the same resting time in the fridge keep the test fair. Each batch is small, just enough for the tasting panel, so little is wasted, and leftover pastry is planned into another dish.

Which sense is it?

What made it unfair?

Two students compare scones made with white and with wholemeal flour. One bakes at 200 degrees and the other at 220 degrees, and they compare how well the scones rise. What is wrong with the test?

• The oven temperature also changed, so it was not a fair test
• They should not have changed the type of flour
• Rise cannot be measured in a food investigation
• Two samples is too many to compare

One peg at a time

A guitarist tuning by ear turns one peg, listens, and only then moves to the next. Turn two pegs at once and you cannot tell which one put the string out of tune. A food investigation works the same way. Decide in advance the single thing you will alter, the single result you will look for, and everything you will hold fixed. Write those three down before you cook, and the results will mean something.

Fill in the planning words

A prediction of what you expect to happen, with a reason, is a _____. The one thing you deliberately change is the _____ variable. What you measure to see the effect is the _____ variable. Everything kept the same in every test is a _____ variable.

Build the plan

Put the stages of planning a food investigation in a sensible order, where each stage depends on the one before.

• State the aim: the question you want to answer
• Research what is already known about the ingredients
• Write a hypothesis, with a reason
• Plan the method, naming every variable
• Plan the sensory test and how results will be recorded

Name the parts of the plan

Assemble a precise description of an investigation into bread.

Find the two slips

A student wrote five statements about planning. Tap the TWO that are wrong.

• Tasting samples should be given codes rather than names.
• The dependent variable is the one you deliberately change.
• Making small test batches helps to reduce food waste.
• A triangle test asks tasters which sample they like best.
• Control variables are kept the same in every test.

Plan the flapjack test

You are planning an investigation into how reducing the sugar changes a flapjack. Decide what to do at each moment.

• You are writing the method and must choose the one thing that will change between batches.
• Your teacher reminds you that food waste must be kept low. How will you plan the quantities?
• Before describing the flavour, you want to know whether tasters can tell the reduced-sugar flapjack from the standard one at all.
• Another group finishes early and offers to bake your second batch in a hotter oven to save time.

Plan a muffin investigation

Plan an investigation into how the amount of sugar affects a batch of muffins. Explain your variables, how you will judge the results, and how you will keep waste down.

• An aim and a hypothesis with a reason
• The independent, dependent and control variables
• Why ingredients working together makes control matter
• A sensory test and why it suits the question
• One way to reduce food waste