As a passionate sommelier and brewer, I can tell you that coffee stouts can indeed contain caffeine. However, it's important to note that not all coffee stouts will have the same caffeine content, as it depends on the brewing process and the amount of coffee used.
When brewing a coffee stout, some brewers use real coffee beans or grounds during the brewing process. This allows the flavors and aromas of the coffee to infuse into the beer, creating a rich and robust taste. In these cases, the caffeine from the coffee beans will also be present in the beer.
On the other hand, some brewers use coffee flavorings or extracts to achieve the desired coffee taste in their stouts. These flavorings may not contain caffeine, as the caffeine is often removed during the extraction process. So, if a coffee stout is made using coffee flavorings without actual coffee beans, it may not contain any caffeine.
It's also worth mentioning that the amount of caffeine in a coffee stout can vary depending on the brewer's recipe and the type of coffee used. Different coffee beans and roasts have varying levels of caffeine, so it's possible that one coffee stout may have a higher caffeine content than another.
Now, let's talk about the impact of caffeine in beer on your sleep. Caffeine is a stimulant that can keep you awake and alert. However, the amount of caffeine in a typical coffee stout is generally much lower than that in a standard cup of coffee. So, unless you have a particularly low caffeine tolerance, enjoying a coffee stout in the evening may not necessarily disrupt your sleep.
Of course, everyone's body reacts differently to caffeine, so it's always a good idea to pay attention to your own tolerance and how it affects your sleep. If you're someone who is sensitive to caffeine or prone to sleep disturbance, you may want to enjoy your coffee stout earlier in the day or opt for decaffeinated versions if available.
Coffee stouts can contain caffeine depending on the brewing process and the use of real coffee beans. However, the caffeine content is generally lower than that of a regular cup of coffee. Ultimately, it's up to you to determine how caffeine affects your sleep and whether or not you want to enjoy a coffee stout as your nightcap brew.