README.md

Chromabrew

Convert SRM, EBC, or a list of Lovibond values to another color scale, or to a hex color.

Color values are provided by Barley Dog Brewery here.

Usage

Install the library:

npm install --save chromabrew

Require the module:

let chromabrew = require('chromabrew');

Pass options which describe a batch to the Batch constructor, or directly to the required module. See the list of accepted options below. Call hex on the returned object to get a color:

new chromabrew.Batch({ srm: 4 }).hex();
// => '#ECE61A'

chromabrew({ srm: 4 }).hex();
// => '#ECE61A'

chromabrew({ ebc: 4 }).hex();
// => '#F8F753'

Convert between color scales:

let batch = chromabrew({ srm: 4 });

batch.srm();
// => 4

batch.ebc();
// => 7.88

batch.mcu();
// => 4.210535199414287

batch.lovibond();
// => 3.407407407407407

Specify which calculation method was used to determine the provided srm or ebc, or which method to use when converting between scales:

let batch = chromabrew({ srm: 14, calculator: 'daniels' });

batch.srm('daniels');
// => 14

// defaults to 'morey'
batch.srm();
// => 14.670088349307665

batch.srm('mosher');
// => 13.099999999999998

// defaults to 'morey'
batch.ebc();
// => 28.9000740481361

batch.hex('daniels');
// => '#B26033'

// defaults to 'morey'
batch.hex();
// => '#A85C37'

Options

Primary Options

Any one of the following options must be passed to the module:

option	description	type
srm	the SRM of a batch	Number
ebc	the EBC of a batch	Number
l or lovibond	the degrees Lovibond of a batch	Number
batch	options describing a batch in detail (see below)	Object

This option may be used in combination with a known color value (srm, ebc, or l) to specify which calculation method was used:

option	description	type
calculator	the SRM calculation method used: 'morey' (default), 'daniels', 'mosher', or 'barry' †	String

† apparently they let anyone create a beer color scale

Batch Options

The following options define the batch primary option:

option	description	type
mcu	the MCU of the batch, if it is already known	Number
v or volume	the total liquid volume of the wort (required)	Number
ingredients	an Array of ingredient options (see below; required)	Array[Object]
litres or liters	whether volume is expressed in litres	Boolean
kilograms or kilos	whether weight of each item in ingredients is expressed in kilograms	Boolean
metric	shortcut to apply both litres and kilograms options	Boolean

Ingredient Options

The following options define each ingredient in the ingredients batch option:

option	description	type
l or lovibond	the value in degrees Lovibond of the ingredient (required)	Number
w or weight	the weight of the ingredient used (required)	Number

Functional Domain

The domain of valid inputs is 0 through 40 SRM. Input values are rounded to the nearest 0.1 SRM within this domain:

chromabrew({ srm: -1 }).hex() === chromabrew({ srm: 0 }).hex();
// => true

chromabrew({ srm: Number.MAX_VALUE }).hex() === chromabrew({ srm: 40 }).hex();
// => true

chromabrew({ srm: Math.PI }).hex() === chromabrew({ srm: 3.1 }).hex();
// => true  

The 'daniels' and 'mosher' SRM calculation scales have a minimum result of 8.4 and 4.7, respectively. Where a provided srm would result in a negative mcu, the mcu is set to 0:

let daniels = chromabrew({ srm: 4, calculator: 'daniels' });

daniels.mcu();
// => 0

daniels.srm();
// => 0

daniels.srm('daniels');
// => 8.4

let mosher = chromabrew({ srm: 4, calculator: 'mosher' });

mosher.mcu();
// => 0

mosher.srm();
// => 0

mosher.srm('mosher');
// => 4.7