Air Pressure Calamities

• Low-pressure systems bring rainy days. When the barometric pressure drops, boiling tends to occur at a lower temperature. These rainy-day air pressure changes may sometimes affect the boiling temperature of your candy sugar. This problem is nothing that a well-working candy thermometer can’t fix. As long as you remember to test the candy thermometer before you begin cooking your candy, reaching the cooking temperature that your recipe calls for should be no problem.

Thermometer Test

• Air pressure changes tend to cause fluctuations in thermometer readings, so test your candy thermometer before beginning any rainy-day candy making. Insert the candy thermometer into a pot of boiling water. The temperature should read 212 degrees Fahrenheit. If it does not, make the necessary adjustments in your recipe. For instance, if the recipe calls for a temperature of 234 F to melt the candy sugar and your candy thermometer reads 210 F, instead of 212 F at boiling, cook the sugar to 236 F.

Humidity Issues

• With rain comes humidity. Humidity tends to wreak just as much havoc on sugar and boiling as air pressure. An increase in humidity does not affect non-crystalline candies, such as hard candy, caramel and taffy, but it does tend to cause crystalline candies, such as fudge and fondant, to turn out softer than expected. A simple temperature adjustment solves this sticky problem. Increase the cooking temperature of your crystalline candy recipe by one degree to compensate for the humidity increase.

Moisture Out

• The humidity that accompanies rainy weather affects candy storage. Even after cooking is complete and cooling is over, candy may still absorb excess moisture, altering the crystalline structure of the final product. The longer the candy remains in the moist air, the softer and stickier it may become. Storing your candy in airtight containers alleviates this problem by placing a barrier between the candy and the moisture in the air, even on the rainiest of days.