As an expert sommelier and brewer, I can tell you that sour beers do indeed have the potential to be lower in carbs compared to regular beers. This is because the microbes used in sour beer fermentation, such as lactobacillus and pediococcus, have the ability to metabolize a wider range of sugars and starches than the typical beer yeast, Saccharomyces cerevisiae.
The metabolic capabilities of these sour beer microbes allow them to break down complex carbohydrates that normal beer yeast cannot ferment. This means that more of the sugars and starches present in the ingredients used to make sour beers can be converted into alcohol and other byproducts. As a result, the residual sugar content in the final product is often lower.
It's important to note, however, that not all sour beers will necessarily be lower in carbs. Some sour beer styles, such as fruit-infused sours or sweetened lambics, may have additional sugars added during the brewing process to counterbalance the sourness. These sugars can contribute to the overall carbohydrate content of the beer.
To provide a more comprehensive answer, I must also mention that the total carbohydrate content of a beer is determined by factors beyond just the fermentation process. The type and quantity of grains used in the brewing process, as well as any additional ingredients such as fruits, spices, or sugars, will all influence the carbohydrate content of the final beer.
In my personal experience, I have observed that sour beers can indeed have a lower perceived sweetness compared to traditional beers. This is due to the tart and acidic flavor profile that sour beers are known for. The presence of these sour and acidic flavors can help balance out any residual sweetness from the fermentation process, creating a more refreshing and crisp drinking experience.
Sour beers have the potential to be lower in carbs compared to regular beers due to the metabolic capabilities of the sour beer microbes. However, the addition of sugars or other ingredients during the brewing process can affect the overall carbohydrate content of the final product. It's always a good idea to check the label or consult with the brewer to get a more accurate understanding of the specific carbohydrate content of a sour beer.