Copied with permission from https://www.arishtam.com/product-page/aristam-homebrewing-guide and https://www.amazon.in/Arishtam-HomeBrew-Probiotics-Indias-homebrew-ebook/dp/B07WSXSCQY
Due to medical reasons, age or just personal preferences, non-alcoholic beverages are gaining popularity nowadays. Even the regular drinkers prefer non-alcoholic version during lunch and business meets. Some commercial NAB (Non-Alcoholic Brews) simply mix the ingredients, carbonate and pack them. However, personally, I prefer the fermented recipes more, where the alcohol is taken out post fermentation than drinking a forced carbonated malty-hopped tea. In order to cater to this niche but premium segment, the brewer needs an ability to take out the alcohol without altering the taste. It may sound simple but it is a big challenge because removing alcohol leaves the fermented brews a lot bitter and sour. In my experience, light beers, with less bittering hops and more aromatic hops are an ideal for such experiments. It is also a good idea to use only specialty malts (low diastatic power) in the non-alcoholic beer to get the required body and mouthfeel. The process of conversion to NAB is divided into five different styles: Membrane: This involves removal of alcohol post fermentation. Industrially, reverse RO is the technique, which is preferred. Here, the ion exchange membrane filters out alcohol leaving the malty beer behind. Internet is full of resources on how to hack a water purifier into a NAB unit. Thermal: Another method used by home brewers is to boil the ethanol off. The beers are heated to 75OC. For the first 10-15minutes, one will smell alcohol, which will then fade away. I find 30 minutes to be ideal to get the best results but some people boil off ethanol for 60 minutes too. Be mindful that, although alcohol has a lower boiling point and will boil off faster, this process also strips the beer off most of the hoppy aromas as well. Vacuum: A more efficient method is vacuum distillation, where the same denaturing is achieved at lower temperatures. This prevents the heat damage to the taste and body as well. Some of my friends have used the condenser from an old refrigerator or commercially available AC service vacuum pump to DIY a vacuum boiling unit. Biological: There are some strains of special yeasts (like Saccharomycodes ludwigii) which are designed for nonalcoholic beer. They give the same sensory feeling as regular yeast but their low attenuation and alcohol tolerance makes it viable to make low alcoholic beverages. Changed mashing: This is what I prefer. I use heavy quantities of crystal and biscuit malts and alter the mashing to produce low fermentable sugars. This way the body and aromas are retained and <1% alcoholic beers can be fermented. Globally, blue labels are used to designate non-alcoholic versions of the regular beers. However, even the best NAB can only mimic the taste but not taste the same as the regular beers.