Does the app need to calculate recipes as well as track them?

Recipe formulation — predicting bitterness, colour, and mash efficiency from a grain bill — is a much deeper problem than tracking, and the existing tools do it well. Version one should let brewers enter targets they calculated elsewhere and focus on what those tools do badly, which is the day-to-day fermentation log on a phone in a garage.

How do I calculate ABV from gravity readings?

The common approximation is (original gravity minus final gravity) multiplied by 131.25, and every brewer knows it is approximate at higher strengths. Show the number to one decimal place, name the formula in a tooltip, and do not present it as more precise than it is — this audience will notice immediately if you do.

How to Build a Homebrew Tracker App with AI (2026)

What a homebrew tracker app needs

Recipe library with grain bill, hops, yeast, and target numbers
Batch log tied to a recipe, with brew-day measurements
Gravity readings over time with automatic ABV and attenuation
Fermentation timeline with stage reminders
Tasting notes and a what-to-change-next-time field

The screens

Screen	What it does
Batches	Active and archived batches with current stage and day count
Batch Detail	Timeline, gravity chart, calculated ABV, and stage actions
Add Reading	Gravity, temperature, and date in three taps
Recipes	Saved recipes with grain bill, hops schedule, and yeast
Tasting Notes	Post-conditioning notes and adjustments for next time

The data model

Recipe: name, style, batchSizeL, targetOG, targetFG, ingredients[], hopSchedule[], yeast
Batch: recipeId, brewedAt, actualOG, volumeL, stage (fermenting | conditioning | done), notes
Reading: batchId, takenAt, gravity, temperatureC
TastingNote: batchId, tastedAt, rating, aroma, flavour, changeNextTime

The build prompt (copy this)

Paste this into ShipNative and it becomes a working React Native app with these screens, navigable in a live preview, in about two minutes:

“A homebrewing batch tracker. Brewers save recipes with a grain bill, hop schedule, yeast, and target original and final gravity, then start a batch from a recipe. During fermentation they add gravity and temperature readings, and the batch detail screen plots gravity over time and calculates ABV and apparent attenuation from the original and latest readings. Each batch moves through stages — fermenting, conditioning, done — with reminders when a stage is due to end or when gravity has been stable for three days. After conditioning, a tasting note records rating, aroma, flavour, and what to change next time. Screens: Batches, Batch Detail with chart, Add Reading, Recipes, Tasting Notes. Show ABV to one decimal place and support both specific gravity and Plato.”

Then iterate with small, screen-specific prompts (“make the primary button bigger”, “add an empty state”), preview on your own phone, and export the full Expo project whenever you want. The full method: how to build an app with AI.

How it makes money

Free for one or two active batches, one-time unlock ($8-15) for unlimited batches and recipe export. A subscription is a hard sell here because brewing is seasonal for most people and an app they open twice a month will not survive a monthly charge. Established competitors like Brewfather exist, so compete on being simple and offline rather than on feature count.

Implementation and the revenue math for every model: how to make money from an app. When you’re ready to ship: App Store and Google Play publishing guides.

Build it now

The prompt above is free to run at shipnative.dev — working homebrew tracker app on your phone today, full code export, no credit card.

How to Build a Homebrew Tracker App with AI