I've followed the recipe for an opera fudge (and several others) as close as I can, yet my fudge always turns out grainy and crumbly. The best results I've gotten have come from not washing down the sides of the pan, but transferring the mixture to a new pan instead.
Why does the fudge always set up like a rock
candyfudge
Related Solutions
I like Kristina's suggestion that you research some of the basics of candy making. I'll answer those questions only briefly.
Generic Candy Questions
- You don't need to heat particularly slowly
This is not like an egg custard where the speed of heating will affect the curdling temperature. You're just trying to get water out. Just don't heat it so fast that you burn the bottom or overshoot the target temp. - Temperature range
The different candy stages have about a 10F range. 2-5 degrees isn't going to make much of a difference but 7-12 will start to. - Adding volatile flavorings to candy
Many flavorings are lost to heat. Such flavorings are added at the end because if they boiled the entire time they would be gone.
Fudgy questions
- Stirring
Stirring isn't required. The syrup won't burn unless you have the heat too high and are using a very cheap pot. Additionally, the syrup absolutely should not be stirred in the final moments of boiling because a sugar crystal might fall in that doesn't get dissolved. During cooling stirring would destroy the fudge because it would all crystallize. - Drying out
This is not a problem. The fudge will not dry out in the time it takes to cool. Losing the gloss
As I wrote in the other answer, the syrup is concentrated and then cooled to a super saturated state and not allowed to crystallize. When it has cooled sufficiently it is mixed like crazy to form your crystals all at once. When this happens the shiny, glossy syrup suddenly fills with crystals and becomes thick and loses the gloss.It is important that the syrup be cooled enough that it is ready to crystallize at the drop of a hat. Again- if you stir it early, as it cools, you will end up with rock candy (more or less). I just leave my candy thermometer clipped on until the target temperature is reached. Make sure the thermometer is clean- one stray sugar crystal can ruin the batch.
The most likely culprit is how well you beat the mixture just before pouring it into the pan. I really like Alton Brown's explanation of the fudge-making process. What you're trying to do is form very small sugar crystals which provide fudge with its fine texture. Those crunchy bits you describe are larger crystal formations which can happen if you have a "seed crystal" remaining in the fudge as it sets. The purpose of stirring the fudge very well before pouring it into the pan is to deliberately form small crystals and break up any larger ones. If you didn't really thoroughly stir even just a few small patches of the fudge, some seed crystals may have developed there.
The clumps you describe in the initial mixture should have dissolved, but working them out would make sure that everything is evenly distributed. You can add the butter to the original mixture for the same reason instead of waiting until the end like the linked recipe recommends. A little bit of corn syrup will help control crystals too. Lastly, stir the fudge like crazy and scrape down as much of the work bowl as you can while you go. If your arms don't feel like they're about to fall off afterwards, you probably should have mixed it more.
Regarding temperature, remember that when simmering your fudge will carry over a couple degrees even after you turn off the heat. So you can kill the burner when your thermometer reaches 235F and monitor until you hit the target temp of 238F.
Quite honestly, fudge-making is a pretty sensitive process, so don't be too broken up if it takes a few tries and a lot of attention to detail before it's perfect.
Best Answer
In Scotland we make a kind of fudge that is deliberatly hard and crystallised known as Tablet. This was a popular treat when I was growing up. Essencially the recipe for tablet, soft fudge, toffee and caramel are quite similar. The difference is made by how you cook and treat the mix as it cools.
Essentially you need to know about sugar boiling points. There are two important levels used: soft boil, and hard boil. My cook books suggest using a sugar thermometer to get the perfect boil but I've never found a sugar thermometer in the shops. Instead I rely on a great deal of practice, the colour, the texture and the drip of the mix to gage how hot the sugar is.
In a soft ball (234–240 °F or 112–115 °C), if you drip the mix onto a very cold surface or into cold water, then touch the drip with your finger, it will be soft like caramel. Additionally the colour will change from cream to yellow/tan.
In a hard ball (250–266 °F or 121–130 °C), dripping again onto a cold surface or into cold water, then touching the drip with your finger, it will be firmer or even hard. The colour will darken slightly to a dark yellow or light brown.
For caramel and fudge you go to a soft boil then cool. For tablet and toffee you go to a hard boil.
The next part is the cooling. This is equally important as the boiling. The faster you cool the mix the smaller the crystals become. The slower, the larger. If you want a caramel or a toffee, you must avoid agitating the mix as it cools. For fudge you should stir the gently as it cools slightly before pouring onto the try. For tablet, the mix should be vigorously stirred until stiff then poured onto a try.