Dipped fruit is one of my favorite items to combine with chocolate. Chocolate strawberries may be the best-known example of this, and while they are indulgent treats, they have several drawbacks. First, chocolate makers charge for the strawberries because they will only use the most picturesque specimens in order to display them. Second, the surface area of the berry is relatively large compared to the actual berry weight. That requires a heavier chocolate coating, since the only way to limit the coating on the berry is by shaking it. Third, you can only add toppings at the dipping stage. This limits the amount and type of toppings you can use. Even a tiny bit of moisture causes a chocolate to thicken and change texture from smooth to lumpy to non-flowable. You can’t reverse this process.
The Science
There are two reasons why water causes a chocolate to thicken. First, sugar particles become sticky as they soften. This stickiness causes particles to connect, resulting in clumping and a lumpy texture in the mouth. The swelling of cocoa powder also causes thickening, as the fibers of the cocoa powder absorb moisture. Moisture reduces both the eating qualities and the flow properties of the chocolate because of the increased friction and the stickiness between particles. This affects the ability of chocolate to flow into the corners of molds, evenly coat a dipped item and dissipate air bubbles upon vibration. Moisture also increases the water activity (Aw) of a chocolate, which shortens the shelf-life and increases the possibility of microbial growth.
Terminology
Aw refers to the free water in an ingredient or product that is available for chemical reactions and interactions with other ingredients; moisture content refers to the total amount of water found in an item. When high-moisture items combine with chocolate, the moisture generally comes from two components. The first is internal moisture that migrates into the chocolate through the fruit’s protective membranes or after removing the fruit’s protective coatings. The second simply comes from water used to wash the fruit.
You can limit moisture by allowing the fruit to air dry and by minimizing the fruits with the chocolate when you temper and form it. In the rest of this article, we will focus on the second option by adding fruit to the surface instead of incorporating the fruit into the tempered chocolate.
Thin Slab Pressing (TSP)
TSP refers to compression of a specified quantity of chocolate between the sides of parchment paper. The compression mechanism can be in a freestyle shape in which only the fold restrains the flow of chocolate upon pressing. Or it can be a mechanism with confined space, such as a hamburger press used in making slabs for this article. (See picture 2.)
To create and load a slab using this mechanism, do the following:
1. Fold parchment paper to create a center line.
2. Pour tempered chocolate on the center of the center line. (See picture 1.)

3. Press the chocolate to its desired shape. . (See pictures 2 and 3.)


4. Open the paper to expose the slab.

5. Load the slab by pressing the fruit into the surface of the pressed chocolate. (See picture 5.)
Note: The chocolate in picture 4 is a milk chocolate containing toffee chips and sea salt. The hot pad in the pictures allows for compression without forming black spots. Those spots would appear if you had used a solid platform, so the particles would contact the other side of the paper and press out the chocolate from under the particles.
Product Examples
TSP is a great option for minimizing the interaction of the fruit with the chocolate. Picture 6 demonstrates the thinness of the slab that you create by using only 20 grams of chocolate to create an oblong slab of roughly five inches. In Picture 7, you can see that the strawberries, cut in half and well-dried, will stick to the slab. We dried the strawberries by patting them with a paper towel. Pictures 8 and 9 demonstrate just a few of the fruit and topping combinations you can add to the slabs. You can change the slab-to-fruit ratio by changing the quantity of the chocolate. That allows you to use a wider variety of fruit, since no one piece is actually the center piece. (See picture 1 as an example.) Using this method, you can prepare different layers of flavors, and you can add whip cream, spices and yogurt to the item.


The dessert we’ve described is extremely indulgent. The fruit items have a short shelf life and the chocolate has a low level of beta crystals, so it melts quickly and releases intense flavor. Because the slab is thin, the chocolate has a light bite. Because we use a lower ratio of chocolate to toppings, we get a richer flavor profile, since the chocolate highlights, rather than overwhelms, the flavors of the fruit and other toppings.


Summary
Creating high-moisture chocolate items using the TSP method provides several benefits for the chocolatier, chef or other chocolate enthusiast. First, it provides a way of getting high-density fruit-to-chocolate ratios by creating a larger platform on which to apply the fruit. Second, it creates an easy way to change or customize or change flavor profiles by adjusting the amount of chocolate in the slab. That also allows you to create multiple topping layers. It also keeps down the overall cost, because you can use lower-premium fruits instead of a single piece of fruit that you’d use as the centerpiece of the dessert.
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