Food acids are used to flavour candy to make it sour. They're naturally present in citrus, apples, berries and more, giving these fruits their "bite." They're inexpensive and indispensable. Learn some food science and find out how to buy and use food-grade acids to make sour candy.
Different Types of Sour Candy
Many different types of sour candy exist. Hard candies, gummy candies and powder candies are some of the most common. They all share one range of ingredients: food-grade acids such as malic acid and citric acid. Other, less common acids in sour candy include tartaric acid and fumaric acid.
Citric, malic and tartaric acids are on the FDA's list of safe additives, although sour candy fans should make sure to brush their teeth after eating any acidic food. Safe does not mean harmless.
When adding acid to a heated mixture such as hard or gummy candy, always add it late in the process, while adding other delicate flavourings, so that the heat does not denature the flavour.
Using Malic Acid in Sour Candy
Malic acid is one of the most common tart flavourings used to make sour candy. It imparts the sour flavour to green apples (malic acid was first discovered in apple juice) and also frequently appears in commercial candy. Too much can cause mouth irritation, but just enough creates a deliciously tart flavour. It offers a stronger sour "hit" than citric acid, with less sharpness. According to information from Bartek, it causes fruit flavours to become enhanced, and can cover the aftertastes of artificial sweeteners.
Food-grade malic acid usually comes packaged as a powder. You can buy it at winemaking and brewing stores or online. Liquid malic acid is mainly sold in factory quantities. Powdered malic acid is highly soluble; just dissolve it before adding it to an application requiring liquid flavours.
Using Other Acids in Sour Candy
Candy-makers also commonly use citric acid. If you're looking for a citrusy, refreshing flavour, try citric acid, which is a very common acidity additive in soft drinks and beverages. Think of the taste of lemon juice. That sharp tang is the flavour profile of citric acid. However, most commercial citric acid, such as that described by DSM Nutritional Products, is made in a fermentation process involving the mould aspergillus niger.
Candy makers can easily acquire citric acid in powder form or in liquid form, which is ideal for hard candy. Remember to add late in the process.
Kool-Aid is a blend of citric acid, food dyes and proprietary artificial flavours. It can serve as a shortcut to a particular flavour of candy, but a serious candy maker working with his own favourite flavours is better off buying pure acids, whether from a brewing shop or a confectioner's supply store.
The secret to making sour candy with Kool-Aid is to use a different ratio of powder to sugar than the ratio suggested for mixing it as a drink. Less sugar and more powder will leave the resulting mixture with a stronger sour flavour.