Bread Holes, Pale Crust and a Soggy Meat Pie
A neighbourhood bakery in Port Harcourt produces 400 loaves of 600 g bread daily and 300 meat pies at weekends. For two weeks customers have complained that loaves have large irregular holes, a pale crust and collapse slightly on cooling; the meat pies have crumbly pastry and soggy bottoms. The baker says the flour is a new delivery of 12% protein flour, the yeast is three months past its best-before date but kept in the freezer, the proofer is a wooden cabinet with a bowl of hot water, and the oven dial reads 220°C although an internal thermometer shows 185°C at the deck. Dough is mixed by hand for 8 minutes, bulk fermented for 45 minutes, shaped and baked after 25 minutes in the proofer. Pastry is made with margarine straight from the fridge, water added until the dough is soft, and filled with warm meat filling; pies are baked on the lower deck.
1. Diagnose the bread faults from the process described. Which cause should be checked first, and how would you test it?
Read the worked answer
The faults have more than one likely cause, so they should be checked in order of cost and ease. First, test the yeast: three months past its best-before date and stored in the freezer can mean dead or weakened cells, especially if the pack was not sealed. Weakened yeast gives slow, uneven fermentation, large irregular holes from uneven gas production, and poor oven spring. Test 5 g yeast with 5 g sugar in 100 ml of water at about 35°C; healthy yeast foams within 10 minutes. If it does not, buy fresh yeast before changing anything else.
Second, check the oven. A dial of 220°C that is actually 185°C means a low bake: pale crust, little oven spring and a dense or collapsing loaf. Calibrate or use an oven thermometer and bake at 220–230°C with steam for the first 10 minutes. Third, examine mixing and proof. Eight minutes by hand may under-develop 12% protein flour, so the gluten cannot hold gas; mix until the dough stretches thin without tearing. A 25-minute proof may be too short or uneven in a wooden cabinet with a bowl of water, so use the poke test and a timer rather than guesswork. Finally, cool on a rack; cooling in the tin traps steam and softens the crust.
2. Calculate the ingredient quantities for a 50 kg flour batch at 62% water, 2% yeast, 2% salt, 1.5% sugar, 2% fat and 0.5% improver. How many 600 g loaves will it make after 2% dough loss?
Read the worked answer
All percentages are based on flour weight, so multiply 50 kg by each percentage. Water = 0.62 × 50 = 31 kg; yeast = 0.02 × 50 = 1 kg; salt = 0.02 × 50 = 1 kg; sugar = 0.015 × 50 = 0.75 kg; fat = 0.02 × 50 = 1 kg; improver = 0.005 × 50 = 0.25 kg. Total dough = 50 + 31 + 1 + 1 + 0.75 + 1 + 0.25 = 85 kg.
Allow 2% loss on dividing, scaling and sticking: 85 × 0.02 = 1.7 kg, so usable dough = 83.3 kg. Number of loaves = 83.3 ÷ 0.6 = 138.8, which means 138 whole loaves of 600 g, with a small piece left over. Without the loss allowance it would be 141 loaves, so the true yield is 138.
Two checks matter. One kilogram of yeast is 2% of flour, which is high for a straight dough and may be compensating for weak yeast; if fresh yeast is used, reduce it to about 1% and extend fermentation. Also, 62% water is a firm dough for 12% flour; if the flour is genuinely strong, the dough may need 64–65% water to develop properly. Record the actual water and dough temperature so the next batch can be compared.
3. Diagnose the meat pie faults and state the rules for making and baking the pastry on the weekend run.
Read the worked answer
Crumbly pastry usually comes from fat that is too cold and hard, so it is not rubbed evenly into the flour, or from too little water, so the dough never comes together. Margarine straight from the refrigerator will stay in lumps. Soggy bottoms come from a warm, wet filling releasing steam into the base and from baking on the lower deck where the base is underbaked before the top browns. Adding water until the dough feels soft can also make a wet pastry that steams.
Rules: use plain flour at about 9–10% protein, not bread flour; weigh ingredients; rub the fat into the flour until it looks like breadcrumbs, using cool hands and a cool room. Add iced water a little at a time, about 50–55% of the flour weight, and stop when the dough just holds together. Rest the pastry wrapped in the refrigerator for 30 minutes before rolling to 3 mm. Chill the meat filling to 5°C or below and drain excess gravy; never fill with hot stew. Egg-wash the rim, seal firmly, cut a vent in the lid and bake on the middle deck at 200°C on a preheated tray until the base is golden and the filling reaches at least 75°C. Rotate the tray halfway. Cool on a rack, not in the tin.