3. Cracker biscuit investigation
Helen's research report below shows how the team investigated different wheat types for cracker biscuits. To have confidence in the collected data, she need to be sure the tests were fair and that sources of error were minimised. Check the methods used below to see how it was a "fair" test.
Characteristics of a good cracker biscuit are:
- Crisp and crunchy with a good feel in the mouth when eaten with a soft centre, not too tough.
- Golden colour.
- Uniform outside appearance, no burnt or over cooked spots.
- Even inside texture. The internal stucture of biscuit and air spaces forms even flakes.
- Not too hard, chewy, firm or tough when eaten.
Use the above characteristics to evaluate the biscuite below. The cross-section shows the internal texture: even flakes apart from one large air space. Outside colour is not golden and varies from brown to white.
MATERIALS AND METHODS
Recipe
Plain flour 220g, 1.5g sodium hydrogen carbonate (NaHC03, baking soda), 26g fat (Frymaster Solid Vegetable Oil) and 3.Og salt (NaCl) into a plastic jar. The liquid ingredient is made by dissolving 2.Og malt extract in 65g warm distilled water in a beaker.
The dough was mixed by machine then rolled to a thickness of 2 mm. A 60 mm biscuit cutter was used to cut the biscuits. Wire baking trays were used for baking at a temperature of 1800C.
The mixer was set to automatically stop after mixing for 5 minutes at 160 rpm; temperature was recorded by inserting a temperature probe into the dough. Dough temperature should be 350C or higher.
Each sheet of dough was placed on a greased baking tray, covered with a tea towel and rested in an oven at 300C for 3 minutes. After 3 minutes, as many biscuits were cut as possible for baking.
The biscuits were baked in an oven for 8 minutes at 2150C.
After baking, the biscuits were covered with a tea towel, and placed into a cabinet to cool for 20 minutes. The biscuits were stored in a plastic container with the lid on, and judged the day after baking. Measurements taken to judge the biscuits were packet length (stack height), packet width, weight of 10 crackers, colour, texture and appearance.
This procedure was repeated for each type of wheat tested so the "test was fair". The only change, variable, was the type of wheat used.
RESULTS
| Sample | Diamondbird | Lorikeet | Snipe | Sunsoft | Thornbill | QAL2000 | Bowie |
| Height of a stack of 10 (cm) | 8.1 | 7.2 | 6.8 | 7.8 | 7.2 | 6.4 | 7.0 |
| Weight of stack of 10 (g) | 71 | 58 | 57 | 58 | 59 | 56 | 57 |
| Colour | brown | golden | golden | yellow | golden | golden | golden |
| Appearance (outside) | dry, thick | OK, streaky | uniform | uniform | uniform | flat | uniform |
| Texture (inside) | hard, chewy |
even, crisp | even, crisp | thick, chewy | even, crisp | firm, tough | crisp, flaky |
| Final Bake Score | 37 | 56 | 54.5 | 50.5 | 59.5 | 35 | 56.5 |
CONCLUSION
Strong hard varieties were totally unsuitable for this product as the texture was hard, and biscuits were hard and chewy. Weak soft wheat was also unsuitable as the biscuits were thin, flat and have a tough inside texture.
Wheat type characteristics again
Diamond |
Lorikeet | Snipe |
Sunsoft |
Thornbill |
Qal2000 |
Bowie |
| strong hard | strong soft | weak soft | strong soft | medium strong soft | weak soft | weak soft |
| bread baking | soft cracker biscuits | sweet biscuits | soft cracker biscuits | pastries, cracker biscuits | sweet biscuits | sweet biscuits |
 |
 |
| wheat grain | investigation flour |