As many of you know, I've been making candy for our Etsy store. For the most part, I've stuck to the toffee recipe which, for the most part, is fail-proof. We briefly had chocolate-covered marshmallow eggs for the Easter season and I've been trying to bring them back as non-Easter shapes for the rest of the year. However, the chocolate coating has been giving me problems...
First of all, I'm purposely avoiding "coating chocolate" or "melting chocolate". That's the stuff you find at the craft stores for making chocolate lollipops and whatnot. I'm avoiding it because it's not really chocolate and we're trying to keep the store as "all natural" as possible. Coating chocolate is mostly vegetable oils, stabilizers, and other stuff that is designed to make it fool-proof so the masses can feel good about themselves crafting moulded chocolates at home. It's great stuff, but it's just not for our store.
In general, my chocolate of choice is and has always been Ghiradelli's Bitersweet (60% cacao) chocolate chips. It's a dark chocolate that's dark enough to satisfy us dark chocolate lovers and light enough that milk chocolate folks generally still like it. I've read some reports that chocolate chips are not good for coating because there are added stabilizers but most say that chips will work just fine if tempered properly.
I have also tried Trader Joe's "Pound Plus" bittersweet bars of chocolate which, presumably, doesn't have all kinds of stabilizers in it. That hasn't helped much either.
Ultimately, I'm seeing white spidering or "bloom" (white snowflake like patterns) on top of the hardened shiny chocolate or the chocolate is drying dull and light-colored with dark brown or light white spots on it. According to everything I've read, this is due to improper tempering.
So What Is Tempering?
Anytime I've ever seen the term "tempering" in a cookbook, it's been pretty vague. Usually, they define it as, "Tempering is the skilled way of melting chocolate to [a certain temperature], cooling it to [another temperature], and then bringing it back up to [a third temperature] so that it dries hard and shiny". Unfortunately, they rarely describe exactly *how* to do this in a practical and home-cook-friendly way. If they do, it's usually some complicated method involving massive amounts of candymaking equipment and a marble slab and they don't give enough detail so you know what you're doing or where you went wrong.
I finally found a couple of excellent articles about tempering, including this one and this one. Here, we actually get the science behind tempering. To sum it up briefly, chocolate is actually in a crystalline structure. When you buy most chocolate, it's already tempered. That's why it's shiny and shelf-stable. When you melt it (at about 110 degrees), the crystals are dissolved. Re-forming these crystals is a tempermental thing because they can re-form into different configurations. The "right" configuration happens to form seed or starter crystals at 70-something degrees. However, if the chocolate continues to cool fast, it'll create lots of the wrong crystals too and you get ugly-looking dull chocolate. So, you must bring it back up in temperature (in the high 80's) to melt the bad crystals but not the good crystals and let it cool very slowly. There's also a right and a wrong time to stir to generate the crystals.
That's all well and good, but how do you *do* it? Most sources (even my toffee recipe) suggest a method that involves heating 2/3 of the chocolate to 110 (or till it's visably melted) in the microwave or double boiler. You then remove the chocolate from the heat source and add the unmelted chocolate. The science behind this is that you're cheating by adding already tempered chocolate back to the hot, un-crystalized chocolate. In theory, you're adding seed crystals in the right formation that should coax the rest of the chocolate back into the right crystalline structure as it cools to the high 80 degree mark. For whatever reason, this usually works with my toffee, where the chocolate is poured and spread-on, but not with hand-dipped candies.
Last night, I tried to make a batch of the marshmallow candies. After reading-up on all this food science, I got out my double boiler and my super-accurate, very expensive instant read thermometer. I carefully melted my good ghiradelli chocolate to about 110 degrees. I removed it from heat and added the unmelted chocolate, stirring to try to get the temperature down into the recommended high 80 range. It never got there and I got impatient around 98-100. So, I sat-down and started dipping. I figured the worst that would happen is the first few would look wrong and the rest would be fine once I got to 87 degrees. By the time I was done, the temp was in the 70's.
After the chocolate had dried, I noticed a pattern on the sheet pan where I had placed the chocolates to dry. The first third of them were dull, soft to the touch, and light-colored with a few barely noticeable dark spots. This was as expected due to my impatience. The second third were dark, shiny, and hard to the touch as they should have been, but they'd developed white bloom patterns. This did not make me happy because it was oh-so-close. The last third were the worst, having the most bloom and an uneven texture.
So what am I doing wrong? I just plain can't figure it out. If there are any experts out there, I'd love to hear your opinion...and please give something more descriptive than "you cooled your chocolates too fast" or "you stirred at the wrong time". I what to know how to FIX the problem...not what the problem is. There's a plethora of info on what causes the problem out on the web...nobody tells you how to fix it.
I have found one technique that fixes the problem but I'm not exactly happy with the results. I have an old recipe for Peanutbutter Balls (aka "buckeyes" in the Mid-west). That recipe calls for adding a small bit of melted parafin wax to the chocolate before dipping. The melted wax is harmless in small quantities and ultimately helps create a shiny coat that looks quite professional. It also prevents blooming most of the time. Unfortunately, I find that it produces a softer chocolate at room temperature and the mouth feel isn't quite right. You get a waxy after-taste.