Tools and calculators
The brewing calculators in the app, including the water calculator and its New Zealand source water.
Open Tools from Home (or from Brew Day). They work on their own, without a recipe, and they’re grouped under headings.
Gravity and alcohol
| Tool | What it does |
|---|---|
| Alcohol | ABV from OG and FG (by the formula in Settings → Brewing defaults), apparent and real attenuation, and the energy in a serve |
| Gravity units | SG, Plato and Brix |
| Gravity correction | How much water to add, or how long to boil, to hit a target gravity. Brew Day links here when the pre-boil gravity is off |
| Refractometer | Corrects a refractometer reading once fermentation has started |
| Gravity Temp | Corrects a hydrometer reading taken hot |
Hops and colour
| Tool | What it does |
|---|---|
| IBU | Bitterness from your hop additions (Tinseth), including whirlpool hops |
| Hop freshness | The alpha acid left in a packet after storage (below) |
| SRM / EBC | Beer colour from a grain bill |
| Colour units | EBC, SRM and Lovibond, with the colour shown |
Yeast: Yeast Pitch Rate for dry yeast, liquid yeast by its production date, slurry, and starter sizes.
Mash and water: Strike and infusion (strike water temperature, and how much boiling water raises the mash to the next rest) and Water / Salts (below).
Packaging: Carbonation, priming sugar for bottles or keg pressure for a CO₂ level.
Units: volume, weight, temperature and pressure.
Recipes: Import Recipe brings in a BeerXML file from Brewfather, BeerSmith or Grainfather; Ingredients adds your own grains, hops and yeasts to the app’s library.
Hop freshness
Hops lose alpha acid as they age, faster when warm and when air gets at them. Enter the alpha acid on the packet, the months since it was packed, where it’s been kept (Freezer, Fridge or Room, or a temperature), and whether it’s in a vacuum or nitrogen pack or a bag. It shows the alpha acid now and how much more to use for the same bitterness, or put the new figure in the recipe as the hop’s alpha.
Lost in 6 months at 20 °C is the variety’s storage stability. Data sheets give it, often as “retains 65% after 6 months at 20 °C” (a 35% loss, the starting figure). An HSI from the supplier can be used instead. The model is Mark Garetz’s: hops age about half as fast for every 15 °C colder.
The water calculator
- Enter your mash and sparge water. Opened from a recipe, it starts with the recipe’s.
- Choose your source water. The main New Zealand supplies are listed with the utility’s own published figures: the Hutt Valley’s Waiwhetu aquifer, Te Mārua (Wellington, Porirua, Upper Hutt), Wainuiomata, Christchurch, and Auckland’s Ardmore and Waikato plants. Under the list it says who published the figures, when, and which ions they don’t publish. RO water and the classic brewing cities are there too, or type your own figures from a water test.
- Choose a target for the style, and Calculate Salt Additions.
- It shows the salts, the split between mash and sparge, the predicted water, the sulfate-to-chloride ratio and the residual alkalinity.
- Attach to a Recipe saves it to a recipe (opened from a recipe: Use for this recipe).
Utility figures are averages, and some ions aren’t published. A home water test is the better number if you have one. See the club’s Brewing water basics.