Add tools for correcting wort during boil

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Version 0.0.8
 
+- Add tools to determine amount of sugar needed to correct wort during brew
 - Add equation to get boiling point at different altitudes
 - Add a gravity-volume converter cli
 - Fix grain conversions

brew/constants.py

@@ -168,5 +168,6 @@
 #: Weight Tolerance, considered equal within this range
 WEIGHT_TOLERANCE = 0.005
 
+# TBD: Set to zero until more testing is completed
 #: Percent of water evaporated during boil, usually 8% or between 8%-10%
-BOIL_EVAPORATION = 0.00
+BOIL_EVAPORATION = 0.0

brew/recipes.py

@@ -14,6 +14,7 @@
 from .constants import IMPERIAL_TYPES
 from .constants import IMPERIAL_UNITS
 from .constants import LITER_PER_GAL
+from .constants import PPG_DME
 from .constants import PPG_CEREAL
 from .constants import SI_TYPES
 from .constants import SI_UNITS
@@ -33,6 +34,7 @@
 from .utilities.color import calculate_srm_morey
 from .utilities.color import calculate_srm_mosher
 from .utilities.color import srm_to_ebc
+from .utilities.efficiency import get_wort_correction
 from .utilities.hops import HopsUtilizationGlennTinseth
 from .utilities.sugar import gu_to_sg
 from .utilities.sugar import sg_to_gu
@@ -276,6 +278,17 @@ def get_final_gravity(self):
     def fg(self):
         return self.get_final_gravity()
 
+    def get_wort_correction(self, current_gu, current_volume,
+                            efficiency=PPG_DME):
+        """
+        Get the amount of sugar to add to correct the wort
+        """
+        return get_wort_correction(current_gu,
+                                   current_volume,
+                                   self.get_original_gravity_units(),
+                                   self.final_volume,
+                                   efficiency=efficiency)
+
     def get_degrees_plato(self):
         """
         Get the degrees plato
@@ -625,6 +638,10 @@ def format(self, short=False):
         kwargs = {}
         kwargs.update(recipe_data)
         kwargs.update(self.types)
+        # Additional format information
+        kwargs.update({
+            'evaporation': BOIL_EVAPORATION,
+        })
 
         msg = u""
         msg += textwrap.dedent(u"""\
@@ -635,7 +652,7 @@ def format(self, short=False):
             Start Volume:       {start_volume:0.1f}
             Final Volume:       {final_volume:0.1f}
 
-            Boil Gravity:       {data[boil_gravity]:0.3f}
+            Boil Gravity:       {data[boil_gravity]:0.3f} (Evaporation @ {evaporation:0.1%})
             Original Gravity:   {data[original_gravity]:0.3f}
             Final Gravity:      {data[final_gravity]:0.3f}
 

brew/utilities/efficiency.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 
 from .sugar import sg_to_gu
+from ..constants import PPG_DME
 
 __all__ = [
     u'calculate_brew_house_yield',
@@ -25,3 +26,21 @@ def calculate_brew_house_yield(wort_volume, sg, grain_additions):
     """
     total_gu = sum([grain_add.gu for grain_add in grain_additions])
     return (sg_to_gu(sg) * wort_volume) / total_gu
+
+
+def get_wort_correction(boil_gravity, boil_volume,
+                        final_gravity, final_volume,
+                        efficiency=PPG_DME):
+    """
+    Get amount of sugar to add to correct wort
+
+    Calculate how much additional DME or LME must be added to correct the boil
+    to hit target final gravity.
+
+    :param float boil_gravity: The gravity of the boil in GU
+    :param float boil_volume: The volume of the boil
+    :param float final_gravity: The desired final gravity in GU
+    :param float final_volume: The desired final volume
+    :param float efficiency: The efficiency of the medium to add
+    """
+    return (final_gravity * final_volume - boil_gravity * boil_volume) / efficiency  # noqa

tests/test_recipes_imperial.py

@@ -280,7 +280,7 @@ def test_format(self):
             Start Volume:       7.0
             Final Volume:       5.0
 
-            Boil Gravity:       1.054
+            Boil Gravity:       1.054 (Evaporation @ 0.0%)
             Original Gravity:   1.076
             Final Gravity:      1.019
 

tests/test_recipes_si.py

@@ -291,7 +291,7 @@ def test_format(self):
             Start Volume:       26.5
             Final Volume:       18.9
 
-            Boil Gravity:       1.054
+            Boil Gravity:       1.054 (Evaporation @ 0.0%)
             Original Gravity:   1.076
             Final Gravity:      1.019