One solution is to re-ferment commercial nonalcoholic beer which is generally available even in dry countries. Of course, this is not worth considering if real beer is available as it won't save you any money or shopping time and there is just as much to carry. But it is an option and the results can be quite good.
Nonalcoholic beer is conventionally brewed beer with the alcohol removed. In recent years, as the demand for the product has increased, the methods for removing the alcohol have become more sophisticated and do far less damage to the flavour than was previously the case. Probably the best products are German as these are subject to strict laws and must be made from only 4 ingredients: malted barley, hops, yeast and water. They are preservative-free which is essential for our purpose. So, how to proceed? ...
Method, for five litres, target ABV = 5%(For a larger brew, simply scale up all the quantities but don't change the timescale)
- Day 1 - Pour 1 small (330 ml) can or bottle of your 0% beer into a glass bowl. Stir in 2 tablespoons granulated sugar. The beer will froth up, which is fine. We want rid of the dissolved CO₂. Add half a teaspoon of dried yeast. Cover and leave in a warmish place.
- Day 2 - Pour 3.3 litres (10 x 330 ml bottles, or equivalent) of 0% beer into a large bowl or bucket. Stir in 450 grams granulated sugar. When the sugar is all dissolved and frothing has subsided, add the fermenting starter from day 1. Cover and leave in a warmish place.
- Day 3 - Pour the fermenting beer through a large funnel into a 5 litre drinking water bottle. Fit the screw-cap but loosely, so that the CO₂ can escape.
- Days 4, 5 - As the head subsides, top up the bottle with more 0% beer to the 5 litre mark (just below the neck). Don't add more sugar. The day 2 addition is all it needs.
- Day 6 or 7 - When bubbling has stopped or slowed to the occasional bubble, tighten the screw-cap and place the bottle in the fridge. This helps the beer to fall clear.
- Day 8 or 9 - Carefully pour the beer into five 1-litre plastic lemonade bottles. Drop one sugar cube into each bottle and cap tightly. Place the bottles in a warmish place for three days then store in a cool, dark place until required. Chill before serving.