Nothing Is Guaranteed

All of these costs assume everything goes to plan. The brew goes smoothly. The fermentation behaves. The beer tastes right. Every can gets filled. Nothing leaks, nothing breaks, nothing gets contaminated.

In reality, things go wrong. A batch doesn't taste right and you can't sell it. A fermentation stalls and you lose a week. A canning run has issues and you lose product. Every failed brew is £3,316 of variable costs — gone. Not to mention the opportunity cost of the time, the fermenter capacity, and the ingredients that could have made beer you could actually sell.

When you're doing four to six brews a month, one lost batch is a significant hit. You've sunk the costs, you've used the capacity, and you've got nothing to show for it. The ingredients don't come with a money-back guarantee.