The Perfect Mince Pie: A Recipe for Excellence

The last Sunday in November is a turning point for most families in Ireland as we finally embrace the coming Christmas season.? It’s also known (in our house anyway) as Stir-Up Sunday! ???At the heart of Stir-Up Sunday is the preparation of the Christmas pudding – a rich, fruity, and boozy dessert that matures over weeks leading up to Christmas.? Its also the day I start making Mince Pies.

This starts the age-old debate surrounding what makes the perfect mince pie. In many households, discussions about the best mince pies often centre on the quality of the pastry, the quantity of mincemeat, the addition of whiskey, oven temperature, and baking time. To settle this culinary conundrum, I dug deep in my Six Sigma Toolbox (Design of Experiments), and together with the kids we embarked on a meticulously designed experiment ?? to unearth the factors that contribute to creating the quintessential mince pie.

Design of Experiments (DOE) is a systematic method to optimize processes, enhance product development, and ensure quality. Integral to Six Sigma and Statistical Process Control (SPC), DOE systematically explores variables to achieve optimal outcomes, in this case, great mince pies.

Key Objectives

The mission was to dissect the mince pie-making process and scrutinize five critical factors that influence the final product: pastry thickness, mincemeat volume, whiskey infusion, oven temperature, and baking time. I Set out to understand how these variables interact and impact three essential attributes: taste, texture, and appearance. The overarching goal was to discover the optimal settings that would simultaneously maximize these three dimensions of mince pie perfection.

Breaking Down the Factors

Here's a breakdown of the factors and their respective low and high levels:

?The mince pies' were quantified by quality on a scale of 1 to 10 for each attribute—taste, texture, and appearance. These scores could then be combined to yield an overall rating. However, our primary focus was to dissect how each factor influenced these individual attributes.

The Scientific Approach

The experimental design was meticulously crafted using Minitab software. We opted for a fractional-factorial 25-1 design comprising 16 runs. This choice allowed us to prepare and taste the pies in close succession. The design incorporated the following factors: pastry thickness, mincemeat volume, whiskey infusion, baking time, and oven temperature.

Setting the Scene: Ingredients & Equipment

To ensure consistency and accuracy, we employed the following ingredients and equipment:

• A batch of homemade shortcrust pastry
• Mincemeat
• Whiskey
• Flour for rolling
• Four half-dozen bun trays
• A rolling pin
• A 3/5 mm marked cocktail stick
• Four sheets of A4 paper
• Two glasses for cutting pastry (one for the base and one for the top)

The oven was preheated to 180°C, and we created a layout plan on paper to match the specific pie combinations. The pastry was divided into two equal portions—one rolled to a thickness of 3 mm and the other to 5 mm. The depth of the pastry was measured at multiple locations using a marked cocktail stick. We used a larger glass to cut out the pie bases and a smaller one for the tops, following the paper grid generated from the DOE run orders. The trays for the 180°C setting were placed in the oven, with the 15-minute tray removed at the specified time and the 20-minute tray removed at its designated time. The oven temperature was then increased to 200°C, and the remaining two trays were baked accordingly. The pies were cooled on wire racks and arranged according to the tray and grid order.

Savouring the Results: The Tasting Phase

Once the pies had cooled, they underwent a meticulous tasting process. Each mince pie was assessed on three key attributes—taste, texture, and appearance—earning a score out of 10 for each category. These scores would serve as the foundation for our subsequent analysis.

Analysing the Factors

1. Taste

The initial focus of our analysis centred on the taste factor. Our effect plot highlighted that factor DE was statistically significant. Other factors and interactions, including B, C, D, E, AC, AE, BD, BE, CD, and CE, were not on the line and warranted further investigation.

The analysis of the residuals showed that none of the assumptions of ANOVA were violated. Mincemeat (B), whiskey (C), and the interaction between time and temperature (DE) were found to be significant for taste. The empirical model derived from this analysis is as follows:

Taste = 7.500 + 0.375XB + 0.375XC - 0.500XDXE

The optimal settings to maximize taste were identified as high mincemeat, high whiskey, and low time and temperature, with the other factors set at their most economical levels.

2. Texture

Moving on to texture, factor A was found to be statistically significant. Other factors and interactions, including E, AC, AD, AE, BD, BE, B, BC, CE, CD, and DE, required further examination. The residual analysis confirmed that none of the ANOVA assumptions were breached. Pastry (A) and the interaction between time and temperature (DE) were deemed significant for texture.

The empirical model for texture emerged as:

Texture = 7.00 - 0.875XA - 0.375XDXE

To optimize texture, it was advisable to opt for low pastry thickness and low time and temperature settings, while keeping the other factors at their most economical levels.

3. Appearance

In the case of appearance, factors A and DE emerged as statistically significant. Other factors and interactions, including B, C, D, E, AB, AC, AD, AE, BE, BC, BD, warranted further scrutiny. The residual analysis once again confirmed that the ANOVA assumptions remained intact. Pastry (A) and the interaction between time and temperature (DE) were established as significant factors for appearance.

The empirical model for appearance was derived as:

Appearance = 7.50 - 0.75XA - 0.625XDXE

To optimize the appearance of mince pies, the ideal settings involved choosing low pastry thickness and low time and temperature, while maintaining the other factors at their most economical levels.

Finding the Perfect Recipe

Having analyzed each response individually and developed empirical models, the next crucial step was to identify the optimum settings that would maximize scores across all three attributes: taste, texture, and appearance. We employed response optimization in Minitab to achieve this goal.

The ultimate combination that delivered excellence in taste, texture, and appearance consisted of:

• Pastry thickness: 3 mm
• Mincemeat volume: 30 ml
• Whiskey infusion: 5 ml
• Baking time: 20 minutes
• Oven temperature: 180°C

Confirming Our Findings

To validate our results, we prepared a new batch of mince pies using the optimized settings. Given the limitations of a single tester's palate, additional tasters were recruited to assist in the final assessment. The scores consistently reflected the excellence of the pies, reaffirming the importance of our statistical analysis in achieving mince pie perfection.

Conclusion

Through a systematic experiment designed around Six Sigma principles and statistical analysis, we have cracked the code for crafting the perfect mince pie. The key takeaways from our research can be summarized as follows:

1. Taste: Maximize mincemeat volume and whiskey infusion while minimizing baking time and oven temperature for the best taste.
2. Texture: Opt for thin pastry and lower time and temperature settings to achieve a delightful texture.
3. Appearance: Choose thin pastry and control time and temperature for visually appealing mince pies.
4. The kids were more interested in the Mince Pies than the Statistics

By following these guidelines, you too can achieve mince pie excellence in your own kitchen this holiday season. The quest for the perfect mince pie may be steeped in tradition, but with a scientific approach, it becomes an achievable culinary delight.