Fudge Factor - Recap

Alton’s at “River Street Sweets” to prove a point – that everyone loves candy. In fact, he says, if you show him a person without at least a few sweet teeth, he’ll show you a person who’s not entirely trustworthy. About then a city councilman walks by and when Alton offers him some fudge, he declines – perhaps making Alton’s case. Most people really like fudge, and will pay as much as five dollars a pound for it. And that’s a shame, because with a pot, a thermometer, some basic ingredients and a little science in their soul, anyone can create their own… Good Eats.

Fudge, Alton tells us, is defined not be its flavor but by its texture. It is a very thick sugar syrup surrounding very small sugar crystals. What’s a crystal? To answer that question Alton brings in crystallographer Karl Hagan. Hagan explains that crystals are solids composed of regular arrays of ions, atoms or molecules. His job is to grow crystals and study their structure. Alton hands him some fudge samples and waits while he studies the candy on his diffractometer. The diffractometer, an instrument for studying crystal properties, tells the tale: the fudge sample contains many very small sugar crystals. Unfortunately, the sample was too…delicious…to be returned.

Alton heads to his kitchen to make more candy. He starts with a heavy sauce pan into which go equal amounts of sugar and water. He brings that to a boil over medium high heat and then slides in a candy thermometer, pausing as the candy syrup boils to recount the history of thermometers.

The clinical thermometer, forerunner of the candy thermometer, was invented by Sir Thomas Allbutt in 1866. The central principle is that liquids expand; Allbutt selected mercury because it does not stick to glass (one of the few fluids with this property) and does not boil until around 675º F. But mercury has its drawbacks, the most significant being that its vapors are toxic. Dyed alcohol is less toxic but less accurate; bimetal dial thermometers are also inaccurate and require frequent recalibration. A modern thermoelectric thermometer catches Alton’s eye. This device exploits the property of certain materials that change electrical resistance in predictable ways when heated or cooled. Alton’s favorite candy thermometer has a power switch to conserve battery energy, a long probe, a strong clip, a good display and even a shield to protect the display from steam.

In the time this explanation has taken, Alton’s sugar has completely dissolved. At this temperature, the sugar (sucrose) molecules have more affinity for the hot water in which they are suspended than for each other. Alton covers his solution with a lid – steam condenses on the lid and runs down the sides of the pot, dissolving any crystals lurking there. Such crystals could cause a chain reaction as the liquid cools, producing a grainy mess.

As the mixture continues to heat, water boils off. The concentration of sugar increases; it is possible to extrapolate the concentration of sugar from the temperature:

230º F – 234º F soft threads
234º F – 240º F soft ball (fudge, pralines)
244º F – 250º F firm ball (caramels)
250º F – 266º F hard ball (divinity, nougat)
270º F – 290º F soft crack (taffy)
300º F – 310º F hard crack (hard candy)

Alton’s looking for a temperature around 236º F so he turns off the heat at just over 232º F – the liquid will “coast” to the desired temperature. Because this solution is supersaturated, Alton cautions that it must be kept very still. Agitation can cause tightly packed sucrose molecules to form a tiny seed crystal, and in a supersaturated solution, a seed crystal will grow quickly into a grainy mess…

Dumping that out, Alton starts over with sugar, unsweetened chocolate, butter, corn syrup, and half & half. This mixture is much less vulnerable to crystallization; even when concentrated, there are many kinds of other molecules keeping the sugar molecules from forming a crystal mass. He cooks this at medium until the sugar dissolves and then increases the heat to boil the solution. While it boils, he butters an 8” x 8” dish and prepares a 10” x 10” piece of parchment by slitting the corners. The parchment goes into the dish and folds up to cover the sides; the butter holds it in place.

Alton covers his pan for three minutes, reminding viewers that steam condensed on the lid dissolves crystals lurking on the sides of the pan. Using the candy thermometer he brings the temperature to 234º F and turns off the heat. If it’s raining or very humid, that temperature needs to be a little hotter. The product will seem harder at first but will soften as it picks up moisture from the air. Once the candy reaches the correct temperature, Alton turns it off and leaves it alone. Now he wants the mix to cool slowly to 110º F. Shirley Corriher, Food Science Diva, explains why: stirring the mixture hot encourages the formation of crystals too soon, and these will grow as the candy cools. Waiting until the candy is mostly cool ensures small crystals that don’t have time to get larger. She recommends a little butter on the surface to discourage drying while the candy cools.

At 110º F, Alton is ready to stir. A mixer would work too much air into the candy, so Alton breaks out a wooden spoon and some elbow grease and stirs his candy until the surface changes from shiny to matte. At that point the stirring is almost done; that’s the time to add vanilla or roasted nuts (if desired). When a spoonful of candy poured back into the bowl clumps together, it’s time to put the candy in the pan. Alton knows he cannot reheat the candy so he works quickly to get it out of the saucepan and into the parchment lined dish, smoothing it with a silicone spatula (wood would just get messy). He sets the candy on the counter for two hours to cool before cutting it. The refrigerator contains too much moisture; candy placed there will turn gummy.

For kids, Alton shares a microwave fudge recipe. This candy isn’t actually fudge – one must create the crystals properly for that – but it is a delicious fudge-like candy. Kids can make it because it doesn't require the cook top.

Alton puts unsalted butter and peanut butter into a microwave safe bowl. He covers that with plastic and pokes a few steam holes, then slides that into the microwave for two minutes. When it’s done, he stirs it, covers it back up, and slides it back in for two more minutes. Then he brings it out to the counter – carefully, that bowl is hot! At the counter he adds vanilla and powdered (confectioner’s) sugar, stirring until the mixture loses its luster. A potato masher works better than a spoon for stirring this candy. Pulling out another prepared baking dish (parchment lined as before) Alton transfers the candy from bowl to dish and smoothes it out. This sort of candy must be refrigerated. A piece of wax paper pressed down on top of it keeps out “fridge funk”.

As Alton closes, hands appear from off camera, snatching away pieces of candy. Distracted, Alton summarizes: your own fudge is right around the corner, on a block on a street in a town we call… Good Eats. Ah, there’s one piece left. Alton reaches for it seconds too late, as the last off camera candy-napper grabs it...

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