Merge pull request #14 from chrisgilmerproj/brewhouse_yield

Add a brew house yield calculator

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Version 0.0.8
 
+- Add method to get grains and hops from recipe by type
+- Make gravity units a property on grain additions
+- Add brew house yield calculator utility
 - Add custom exceptions
 - Improve error messages for faster debugging
 

brew/grains.py

@@ -282,6 +282,28 @@ def get_weight_map(self):
             u'dry_weight': round(self.get_dry_weight(), 2),
         }
 
+    @property
+    def gu(self):
+        return self.get_gravity_units()
+
+    def get_gravity_units(self):
+        """
+        Get the gravity units for the Grain Addition
+        :return: Gravity Units as PPG or HWE depending on units
+        :rtype: float
+
+        Gravity Units are really a property of whole grains, not of extracts.
+        Therefore the units will always be represented after the weight has
+        been converted from an extract weight to a cereal weight.
+        """
+        # Pick the attribute based on units
+        if self.units == IMPERIAL_UNITS:
+            attr = u'ppg'
+        if self.units == SI_UNITS:
+            attr = u'hwe'
+
+        return getattr(self.grain, attr) * self.get_cereal_weight()
+
     def to_dict(self):
         grain_data = self.grain.to_dict()
         return {u'name': grain_data.pop('name'),

brew/recipes.py

@@ -36,6 +36,8 @@
 from .utilities.sugar import gu_to_sg
 from .utilities.sugar import sg_to_gu
 from .utilities.sugar import sg_to_plato
+from .validators import validate_grain_type
+from .validators import validate_hop_type
 from .validators import validate_optional_fields
 from .validators import validate_percentage
 from .validators import validate_required_fields
@@ -195,20 +197,14 @@ def get_total_points(self):
         :return: PPG or HWE depending on the units of the Recipe
         :rtype: float
         """
-        # Pick the attribute based on units
-        if self.units == IMPERIAL_UNITS:
-            attr = u'ppg'
-        if self.units == SI_UNITS:
-            attr = u'hwe'
-
         total_points = 0
         for grain_add in self.grain_additions:
             # DME and LME are 100% efficient in disolving in water
             # Cereal extraction depends on brew house yield
             efficiency = self.percent_brew_house_yield
             if grain_add.grain_type in [GRAIN_TYPE_DME, GRAIN_TYPE_LME]:
                 efficiency = 1.0
-            total_points += getattr(grain_add.grain, attr) * grain_add.weight * efficiency  # noqa
+            total_points += grain_add.gu * efficiency  # noqa
         return total_points
 
     def get_original_gravity_units(self):
@@ -550,6 +546,26 @@ def get_total_wort_color_map(self):
             },
         }
 
+    def get_grain_additions_by_type(self, grain_type):
+        """
+        Return grain additions by given grain_type
+
+        :param str grain_type: The type of grains to return
+        :return: list of GrainAddition objects
+        """
+        validate_grain_type(grain_type)
+        return [grain_add for grain_add in self.grain_additions if grain_add.grain_type == grain_type]  # noqa
+
+    def get_hop_additions_by_type(self, hop_type):
+        """
+        Return hop additions by given hop_type
+
+        :param str hop_type: The type of hops to return
+        :return: list of HopAddition objects
+        """
+        validate_hop_type(hop_type)
+        return [hop_add for hop_add in self.hop_additions if hop_add.hop_type == hop_type]  # noqa
+
     def to_dict(self):
         og = self.og
         bg = self.bg

brew/utilities/efficiency.py

@@ -0,0 +1,27 @@
+# -*- coding: utf-8 -*-
+
+from .sugar import sg_to_gu
+
+__all__ = [
+    u'calculate_brew_house_yield',
+]
+
+
+def calculate_brew_house_yield(wort_volume, sg, grain_additions):
+    """
+    Calculate Brew House Yield
+
+    :param float wort_volume: The volume of the wort
+    :param float sg: THe specific gravity of the wort
+    :param list grain_additions: A list of grain additions in the wort
+    :type grain_additions: list of GrainAddition objects
+    :return: The brew house yield as a percentage
+
+    Brew House Yield is a function of the wort volume, the measured specific
+    gravity, and the grain additions used to make the wort.  This equation is
+    thrown off by use of LME or DME since both have 100% efficiency in a brew.
+    A better measure is to look at just the grains that needed to be steeped
+    seperately and measure the specific gravity of that process.
+    """
+    total_gu = sum([grain_add.gu for grain_add in grain_additions])
+    return (sg_to_gu(sg) * wort_volume) / total_gu

tests/test_grains.py

@@ -246,6 +246,16 @@ def test_ne_units(self):
     def test_ne_grain_class(self):
         self.assertTrue(pale_add != pale)
 
+    def test_gu(self):
+        out = self.grain_add.gu
+        expected = 516.52
+        self.assertEquals(out, expected)
+
+    def test_get_gravity_units(self):
+        out = self.grain_add.get_gravity_units()
+        expected = 516.52
+        self.assertEquals(out, expected)
+
     def test_to_dict(self):
         out = self.grain_add.to_dict()
         expected = {u'name': u'pale 2-row',

tests/test_recipes.py

@@ -2,6 +2,10 @@
 import sys
 import unittest
 
+from brew.constants import GRAIN_TYPE_CEREAL
+from brew.constants import GRAIN_TYPE_LME
+from brew.constants import HOP_TYPE_PELLET
+from brew.constants import HOP_TYPE_WHOLE
 from brew.constants import IMPERIAL_UNITS
 from brew.constants import SI_UNITS
 from brew.exceptions import RecipeException
@@ -149,6 +153,18 @@ def test_hops_units_mismatch_raises(self):
         self.assertEquals(str(ctx.exception),
                           u"pale ale: Hop addition units must be in 'imperial' not 'metric'")  # noqa
 
+    def test_get_grain_additions_by_type(self):
+        grain_additions = self.recipe.get_grain_additions_by_type(GRAIN_TYPE_CEREAL)  # noqa
+        self.assertEquals(grain_additions, self.recipe.grain_additions)
+        grain_additions = self.recipe.get_grain_additions_by_type(GRAIN_TYPE_LME)  # noqa
+        self.assertEquals(grain_additions, [])
+
+    def test_get_hop_additions_by_type(self):
+        hop_additions = self.recipe.get_hop_additions_by_type(HOP_TYPE_PELLET)  # noqa
+        self.assertEquals(hop_additions, self.recipe.hop_additions)
+        hop_additions = self.recipe.get_hop_additions_by_type(HOP_TYPE_WHOLE)  # noqa
+        self.assertEquals(hop_additions, [])
+
 
 class TestRecipeBuilder(unittest.TestCase):
 

tests/test_recipes_imperial.py

@@ -60,7 +60,7 @@ def test_get_total_points_lme(self):
                         units=IMPERIAL_UNITS)
 
         out = recipe.get_total_points()
-        self.assertEquals(round(out, 2), 387.39)
+        self.assertEquals(round(out, 2), 516.52)
 
     def test_get_total_points_dme(self):
         pale_dme = GrainAddition(pale,
@@ -74,7 +74,7 @@ def test_get_total_points_dme(self):
                         units=IMPERIAL_UNITS)
 
         out = recipe.get_total_points()
-        self.assertEquals(round(out, 2), 310.06)
+        self.assertEquals(round(out, 2), 516.77)
 
     def test_get_original_gravity_units(self):
         out = self.recipe.get_original_gravity_units()

tests/test_recipes_si.py

@@ -71,7 +71,7 @@ def test_get_total_points_lme(self):
                         units=SI_UNITS)
 
         out = recipe.get_total_points()
-        self.assertEquals(round(out, 2), 1466.71)
+        self.assertEquals(round(out, 2), 1955.61)
 
     def test_get_total_points_dme(self):
         pale_dme = GrainAddition(pale,
@@ -85,7 +85,7 @@ def test_get_total_points_dme(self):
                         units=SI_UNITS)
 
         out = recipe.get_total_points()
-        self.assertEquals(round(out, 2), 1173.36)
+        self.assertEquals(round(out, 2), 1955.61)
 
     def test_get_original_gravity_units(self):
         out = self.recipe.get_original_gravity_units()

tests/test_utilities_efficiency.py

@@ -0,0 +1,17 @@
+# -*- coding: utf-8 -*-
+import unittest
+
+from brew.utilities.efficiency import calculate_brew_house_yield
+from fixtures import recipe
+
+
+class TestEfficiencyUtilities(unittest.TestCase):
+
+    def setUp(self):
+        self.recipe = recipe
+
+    def test_calculate_brew_house_yield(self):
+        out = calculate_brew_house_yield(recipe.final_volume,
+                                         recipe.og,
+                                         recipe.grain_additions)
+        self.assertEquals(round(out, 3), self.recipe.percent_brew_house_yield)