It is easy to add too much spice to soup, especially if you do not cook regularly or rarely make soup. Some spices take time to infuse into all the liquid in a soup. Many impatient cooks make the mistake of adding more instead of waiting, with the result that the dish becomes too spicy by the time it is to be served. The same situation can occur if you misread your recipe and put in a tablespoon of cayenne pepper into your soup instead of a teaspoon. Whatever the reason for the extra spice in your soup, there are solutions.
Diluting a dish is one of the easiest ways to reduce overly concentrated flavors, including the heat from spices. It will work whether the excessive spiciness is because of chili peppers or some other spice. It so happens that soup is one of the easiest dishes to dilute due to its high liquid content. All that is needed to lessen the spice in a soup is to add more of the base stock as well as more vegetables, meat, or other ingredients. Add more stock rather than water to help preserve the flavor. You may also need to increase the amounts of some spices to ensure that the extra liquid and other ingredients do not make it bland. Another option is to make another batch of soup and to add it to the first.
Of course, dilution will mean that you have more leftovers but at least you won’t have to throw your soup out.
If the heat is coming from chili peppers, adding dairy to your soup may work. Dairy contains a protein called casein that binds with the capsaicin in peppers, which is the compound that makes them hot. This allows the dairy products to tone down their heat. Add milk, half and half, or cream to your soup to help neutralize excessive chili pepper heat. Note this is very similar to the best way to curb chili burn.
Another way to add fat to a soup is in the form of a nut butter like peanut butter. Note that this may be inappropriate for most soups, but may work as an alternative to dairy products in some. Aside from peanut butter, your other options include cashew butter and tahini paste.
If the soup’s heat is coming from black pepper, then you can add alcohol for a similar effect. The compound that gives black pepper its heat is called piperine and is soluble in alcohol. Depending on the type of soup, you can use wine or even vodka to neutralize the heat.
You can use the same technique that Thai cooks use, which is to add an acid. An acidic ingredient may be useful for dampening the heat, especially when the spiciness is coming from chili peppers. As with the dairy and alcohol options above, this method may not be suitable for all soups. Consider your flavor profile carefully before you add acidic ingredients to your soup. Your options include tomato, citrus, or vinegar.
Make it sweeter
A little sugar or honey may be useful for balancing out the flavors in some soups. Note that you need just a small amount of sweetener to help counteract the spice. Going overboard with sweetness can completely ruin the flavor profile of your dish, so be careful.