Monday, June 22, 2009

Gluten Formation is Essential for Puffy Scones

Sun K, Tsai J, and Hsieh J.


Bad scones afflicts cafes, hotels and restaurants serving breakfasts across North America (I would venture to declare "the world" but I have never ventured outside North America...but will in October!). Characteristics of bad scones include dryness, flatness, dryness, tastelessness, dryness, and the density of a 75% polyacrylamide gel. Courtesy of Dr. Sun (St. Michael's Hospital, Toronto, ON), we have procured jars of real clotted cream (well, almost real, these are pasteurized). It would be blasphemy to apply such examples of gourmet divinity to sub-optimal-tasting scones. In this study we aimed to rectify, or at least alleviate, chronic bad scone-ness to accompany our clotted cream. We used Cook's Illustrated's Blueberry Scone recipe to see if it really was indeed, the best scone recipe ever.

First task was to confirm identity of clotted cream. Clotted cream consists of 55% milk fat. Double Devon cream (sold at many grocery stores throughout the GTA) is 48%. Whipping cream is 35%, but requires dedicated whipping to achieve spreadable consistency. If one thinks the fat content of Double Devon cream is excessive enough, and that anyone would be crazy to go to great lengths to procure clotted cream, consider this: skim milk is 0% fat and homogenized milk is 3.25% fat. There is only a 3.25% difference in fat content yet the taste and perceived texture is markedly different. Imagine with a fat content difference that is 7%! Believe me, the gustatory CD36 receptors can tell.

Removing said jar of clotted cream from 4 degrees revealed that clotted cream is completely solid - telling of the high saturated fat content. Sufficiently convinced with the high fat content of this jar, we proceeded to make the scones.

Unfortunately, as a testament to the importance of good pantry organization, I was unable to locate my bag of all-purpose flour. However, cake flour was readily on hand, right beside my bag of rice and underneath the bag of coffee. Recipe called for grated butter, but to minimize handling of frozen butter with 37 degree-ish hands, butter was pulsed in a food processor (Kitchenaid) with flour, sugar, baking soda, baking powder, salt, and lemon zest until the size of peas. Homogenized milk and full-fat sour cream was mixed, and then folded into the butter and flour mixture. The batter was handled as described in Protocols, frozen blueberries were pushed in, and 8 triangular scones were baked in a preheated 425 degree oven on a silpat-covered airbake (very important to avoid excessive browning on the underside).

Figure 1. Blueberry scoes juxtaposed to clotted cream and strawberry Bon Maman.

Blueberry scones emerged from the oven looking acceptably puffy (Figure 1). Taste revealed a very moist, almost cake-like texture. The appreciable rising is attributable to the acid-base reaction between the baking soda (sodium bicarbonate) and sour cream (lactic acid) to release carbon dioxide. Satisfying, but Dr. Sun insisted that all-purpose flour be used in the next experimental batch.

Recipe was followed as described above, except with the substitution of all-purpose flour for cake flour. Chopped crystallized ginger (Dan-D-Pak) was used in lieu of blueberries, but these were not expected to have affected results. Note: there is no such thing as too much crystallized ginger. All-purpose crystallized ginger scones emerged from the oven and to our amazement, the scones were even puffier (Figure 2) and almost double in height compared to cake flour blueberry scones.

Figure 2. Crystallized ginger scones juxtaposed with clotted cream and Lyle's Golden Syrup.

Application of clotted cream and bon mamman jam indicated that all-purpose flour also leads to a more fluffy and scrumptious scone (Figure 3).

Figure 3. Blueberry (cake flour) scones with jam on the bottom, and then clotted cream on top.


The main difference between cake flour and all-purpose flour is that cake flour contains no gluten, the protein that provides bread and other baked goods with its structural integrity. Such gluten (some of which would have formed during kneading) was necessary to maintain the air pockets of carbon dioxide released from the sodium bicarbonate/lactic acid reaction during baking. In the cake flour scones, without interchain disulphide bonds and tyrosine-tyrosine crosslinks, and some hydrogen bonds, the batter immediately collapses after the bubble of carbon dioxide is formed.
In conclusion, cake flour is good for making cake, but all-purpose flour and thus gluten formation is essential for a fluffy scone.

Other tasting notes: Lavender Vidal jelly works surprisingly well with brie.

Figure 4. (Clockwise from top) Lavender, Cranberry, and pink peppercorn scones.

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