Skip to content

Latest commit

 

History

History
97 lines (69 loc) · 3.02 KB

calculations.md

File metadata and controls

97 lines (69 loc) · 3.02 KB
Raw

Calculations

Many attributes of a beer, like the alcohol content and bitterness, can be calculated from the source ingredients. Brewtility has many of the calculations required by the BeerXML specification, and other convenience functions packaged under brewtility.calculations. The following is a list of supported functions:

Beer Color Calculation

Given a collection of common-beer-format conforming fermentables, and a conformed batch-size in liters, return the projected color of the beer in one of the following color scales:

  • Malt Color Units (MCU)
  • Standard Reference Method (SRM)
  • European Brewery Convention (EBC)
  • Lovibond
  • Red/Green/Blue/Alpha (RGBA)
(:require [brewtility.calculations :refer :all]
          [common-beer-format.data.fermentables.grains :as grains]
          [common-beer-format.data.fermentables.adjuncts :as adjuncts])

(def recipe-fermentables
  [(assoc (:rye-malt grains/grains) :amount 7)
   (assoc (:pale-malt-2-row-us grains/grains) :amount 3)
   (assoc (:rice-hulls adjuncts/adjuncts) :amount 2)
   (assoc (:grits adjuncts/adjuncts) :amount 4)])

(def batch-size 15)

(calculate-malt-color-units recipe-fermentables batch-size)
;; => 20.784

(calculate-srm-color recipe-fermentables batch-size)
;; => 21.273

(calculate-ebc-color recipe-fermentables batch-size)
;; => 20.41.907

(calculate-lovibond-color recipe-fermentables batch-size)
;; => 41.907

(calculate-rgba-color recipe-fermentables batch-size)
;; => "rgba(149,45,0,1)"

Gravity and ABV Calculation

Given a collection of common-beer-format conforming fermentables and a conformed batch-size in liters, project the original gravity and estimate the ABV.

(:require [brewtility.calculations :refer :all]
          [common-beer-format.data.fermentables.grains :as grains]
          [common-beer-format.data.fermentables.adjuncts :as adjuncts])

(def recipe-fermentables
  [(assoc (:rye-malt grains/grains) :amount 7)
   (assoc (:pale-malt-2-row-us grains/grains) :amount 3)
   (assoc (:rice-hulls adjuncts/adjuncts) :amount 2)
   (assoc (:grits adjuncts/adjuncts) :amount 4)])

(def batch-size 19)

(calculate-potential-gravity fermentables batch-size)
;; => 1.146

(calculate-potential-final-gravity fermentables batch-size)
;; => 1.036

;; Reminder: All percentages are treated as decimals
(calculate-potential-abv fermentables batch-size)
;; => 0.147

(def my-yeast-attenuation 1.00)

;; Reminder: All percentages are treated as decimals
(calculate-potential-abv fermentables batch-size my-yeast-attenuation)
;; => 0.197

IBU Calculation

Given a collection of common-beer-format conforming hops, batch-size, and potential-gravity, calculate the number of IBUs generated.

(:require [brewtility.calculations :refer :all]
          [common-beer-format.data.hops.both :as hops])

(def hops
  [(assoc (:el-dorado hops/both) :amount 0.01 :time 60)]
   (assoc (:horizon hops/both) :amount 0.02 :time 10)])

(def batch-size 15)
(def potential-gravity 1.03)

(calculate-recipe-ibus hops batch-size potential-gravity)
;; => 42.795