Fudge, Fortune, and Phase Transitions
I've been on a bit of a cooking kick lately. I'd like to say that my motivation is to eat healthier, or to learn a marketable skill, or even to impress the ladies, but mostly it's an excuse to buy some cool gadgets for the kitchen. (I don't know how I got along without an electric knife with interchangable meat-carving and bread-cutting blades.)
Anyhow. I've had some success with chicken and beef dishes, various pastas, salads, vinaigrette dressings, etc. Recently I thought I'd like to tackle some dessert recipies, if only because they make my apartment smell nicer than when I'm preparing, say, garlic bread (made with my own garlic butter), pasta and a garlic tomato sauce, and cheese, crackers, and roasted garlic appetizers.
Today, inspired by my Tivo's recent recording of Good Eats: Fudge Factor (EA1G05: transcript), I decided to try and make fudge. Fudge, of course, is classified as a candy. It's essentially sugar with a little bit of stuff added. First, I needed a candy thermometer. As tempting as it was to hunt down a fancy digital candy thermometer, I settled for a $10 glass-alcohol model from Bed Bath & Beyond. (I picked up a nice All-Clad 3 qt sauce pan as well, but that's another story.)
The fudge recipe, courtesy of the calculatingly clever curator of culinary concuspience, Alton Brown, is quite simple. The devil, rather than being in the details, is lurking in the timing. I, unfortunately, did not get the timing quite right, and as a result my fudge was less a fudge and more a crumbly, fudge-like amalgam of sugar crystals and chocolate. Don't get me wrong -- it's not bad. It's just a pretty ugly fudge, and it doesn't have the right melts-in-your-mouth consistency. But I'm pretty sure I know where I went wrong, so I'll share with you my addenda to the recipe, in the event that you attempt it yourself:
First, as you can glean from watching Alton's show (or reading the transcript, making successful fudge is entirely dependent on making your sugar crystallize with a very fine crystal size. There are basically three stages to this reciple: The Melting, The Heating, and The Cooling. As you might guess, the sugar in the recipe undergoes a series of phase transitions during these stages: from a solid to a liquid (in solution), to a super-saturated solution, to a solid. The crucial things are to keep track of temperature and time.
Stage 0: The Errata
A couple of quick corrections to the recipe: Use unsalted butter (the reciple online doesn't specify, but the show does). Also, make sure you get light corn syrup; there's a dark corn syrup that's much closer to molasses than to glucose, and you don't want to use that. And finally, make sure your sauce pan doesn't suck. This recipe is all about controlling heat, and if your pan doesn't have a good, heavy base to help heat and cool the syrup evenly, you might as well give up now.
Stage 1: The Melting
I don't have a lot to add here. The most important thing is to make sure that absolutely all the chocolate and (especially!) all the sugar has been dissoved before brining the syrup mixture to a boil. How can you tell? Stir thoroughly, and use your tasting spoon (you do keep a tasting spoon handy, right?) to, you know, taste the syrup. If you've done your job well, you'll taste no solid sugar crystals.
Note that once all the chocolate has melted, the syrup will look slightly translucent with tiny brown flecks mixed in. Do not be alarmed -- this is a Good Thing. As long as you have only teeny-tiny flecks of chocolate and not big goopy lumps of chocolate, you're good to go.
Phase Transition: Your sugar (and other consituent ingredients) will go from a solid to a liquid syrup solution.
Stage 2: The Heating
After you've covered and boiled the syrup, its time to crank up the heat. Make sure your candy thermometer is properly positioned in your saucepan, or you'll get incorrect temperature readings and you'll blow right by the Soft Ball phase and right on into Hard Crack phase, and you'll have nothing but a bizarre fudgey jawbreaker mess on your hands. (I'm really only guessing about that last part.)
Proper placement is best determined before you've gone and dumped all your crap into the sauce pan. In my case, proper placement of the alcohol candy thermometer is thusly: Align the clip so that the metal bracket holding the thermometer is touching the bottom of the pan. (The bulb doesn't actually touch the metal bracket, so you'll still be getting the temperature of the syrup and not the pan.) You own thermometer model may vary. (Also note what A. B. says: no bi-metal thermometers! They suck.)
Note about target heating temperature: On the show, A. B. says to cut the heat at 232 deg F and let the syrup coast to 235 or 236. The recipe says to "remove from heat" at 234 deg F, which I take to imply moving the sauce pan to a cool burner on your stove. In my experience (of, admittedly, one data point), following the recipe and moving the pan to a cool burner at 234 (as opposed to returning to the still-hot burner) caused the syrup to coast up to 236 as desired. Either way is probably fine.
Phase Transition: As the water boils off of the syrup, the temperature will rise, and the sugar in the mixture will become super-saturated. The candy thermometer will help you manage the temperature of the syrup and, therefore, also the concentration of the sugar in solution.
Stage 3: The Cooling
This is the most important stage, so pay close attention and don't screw it up! It can take anywhere from 10 minutes (as per the recipe) to an hour or so (as per my one-data-point experience) for the syrup to cool. This doesn't mean you can go off an dilly-dally around while the stuff cools down -- keep a close eye on the temperature or you'll come back to a pan of solid pseudo-fudge, and that would suck.
When you add the last 1.5 Tbsp of (unsalted!) butter to the pan, slice the pads fairly thin (you did keep the butter cold, didn't you?) so that they float near the surface rather than sink. The point of the butter is to prevent the surface of the syrup from developing a skin or from crystallizing too early, and sunken butter chunks are not going to be helpful here.
Note about target cooling temperature: On the show, A. B. says cool to 110 deg F, but the recipe says 130 deg F. I split the difference and let it go to 120 deg F, and that seemed to work fine. However, I didn't add any roasted nuts to the syrup (although I did add vanilla extract, of course). Per A. B., adding nuts will cause the syrup to cool much faster, so you're probably better off waiting for 130 deg F instead. If you miss your target temperature, you're probably screwed -- heating up the syrup again will just make things worse.
As the syrup cools, DON'T TOUCH IT! I'm serious here -- leave the thing alone. Don't move the pan, don't go cooking other stuff on your stove or in your oven, and if you're flat-footed or limping or some crazy thing like that, for crying out loud put on some socks or something so you don't go thumping around the damn kitchen!
Why don't touch? Because that's what A. B. told you to do. Okay. What's happening as the solution cools is that the solubility of the sugar in the solution will drop. This means that what was just a saturated sugar solution at 236 deg F will become super-saturated at 130 deg F. This works fine, because there's enough liquid in the syrup to support a super-saturated sugar solution as long as you don't touch it. If you touch it, the slight vibrations in the pan can cause the sugar molecules to form seed crystals, and the excess sugar in the super-solution will start to "fall out" of the syrup as tangly crystalline strands. And that is a bad, bad thing for your fudge. This is also why you want to be careful to avoid having any undissolved solids stuck to the side of the pan -- those solids could act as nucleation sites for crystallization and the same thing will happen and ruin your fudge. And it should absolultey go without saying that while you're not touching the pan as it cools, don't stir it either! Resist the urge. Don't stir in the butter, just don't stir it. Until the syrup has cooled to the target temperature, hide the spoon -- put it in a draw, shove it down your pants, I don't care. Just don't touch the cooling syrup.
Phase Transition: I covered this in the above paragraphs.
Stage 4: The Stirring
What? Didn't I say there are only three stages? Well, I lied. This is actually the fifth stage, anyhow.
Make sure your vanilla and (if you're crazy and like this sort of thing) your roasted nuts are ready to add as soon as the syrup cools to the target temperature. Also take the spoon out of your pants and make sure your greased pan is ready to accept the syrup.
Did I say Stage 3 was the most important? Well, Stage 4 is really the most important, and I'm not kidding you. Trust me, this is where I screwed up my fudge and where you can right my wrong. So pay attention.
As soon as your syrup is cool enough, dump in the vanilla (and the lame nuts). Now: STIR THAT SYRUP LIKE A PSYCHOPATH ON PHENCYCLIDINE. The syrup will be thicker than it looks, so put some muscle into it! Make sure to scrape the sides and bottom as you go, because you need to make sure to thoroughly stir all that stuff together.
Your stirring motion is what sets off the crystallization of the sugar in the super-solution. You want to stir really fast because the faster you stir, the smaller your sugar crystals will be. And better fudge means smaller crystals. Keep stirring! Stir like mad!
Except not for too long! According to A. B. and the recipe, you need to watch for the syrup to go from a shiny-brown appearance to a slightly duller matte-brown appearance. The difference is fairly subtle, and it only happens after you've been stirring for a little bit, so keep an eye on your syrup!
Once you see it go from shiny to dull (and if you find yourself saying, "hmm, I wonder if that dullness is dull enough," then IT IS DULL ENOUGH), then you need to get that syrup into the pan pronto, or it will begin to "set up" in the pan and, once again, you're screwed. The term "set up" actually means that the sugar crystallization process starts to affect the entire batch of syrup. Once it's started, there's no stopping it, so you'd better be getting the syrup into the pan or you'll be eating it from the sauce pan you cooked it in.
Get it in the pan, smooth it out (but don't press too hard), and let it sit and cool.
There, you're done! And hopefully you didn't mess it up too badly.
I hope this helps you be more successful at making fudge.