Add a bunch of properties for beer calculation.

beer/models.py

@@ -82,6 +82,97 @@ class BatchRecipe(CustomModel):
     efficiency = models.DecimalField(max_digits=6, decimal_places=2, default=75)
     batch_size = models.DecimalField(max_digits=6, decimal_places=2, default=11)
 
+    @property
+    def fermentables(self):
+        return [x for x in list(self.recipefermentable_set.all())]
+
+    @property
+    def hops(self):
+        return [x for x in list(self.recipehop_set.all())]
+
+    @property
+    def final_volume(self):
+        return float(self.batch_size) + self.hop_water_loss + self.net_kettle_deadspace + self.kettle_hose_loss
+
+    @property
+    def ferm_yield(self):
+        ferm_yield = 0
+
+        for f in self.fermentables:
+            if f.fermentable.fermentable_type == 3: # Is sugar
+                ferm_yield += f.quantity * (f.fermentable.potential - 1) * 1000
+            else:
+                ferm_yield += f.quantity * (self.efficiency / 100) * (f.fermentable.potential - 1) * 1000
+
+        return float(ferm_yield)
+
+    @property
+    def mash_yield(self):
+        mash_yield = 0
+
+        for f in self.fermentables:
+            if f.fermentable.fermentable_type != 3: # Is not sugar
+                mash_yield += f.quantity * (self.efficiency / 100) * (f.fermentable.potential - 1) * 1000
+
+        return float(mash_yield)
+
+    @property
+    def original_sg(self):
+        return round(1 + self.ferm_yield / self.final_volume / 1000, 3)
+
+    @property
+    def pre_boil_sg(self):
+        return self.ferm_yield / (self.final_volume + self.boil_off_gph)
+
+    @property
+    def hop_water_loss(self):
+        hop_absorption = .025 # gallons per ounce
+        return sum([float(x.quantity) * hop_absorption for x in self.hops])
+
+    @property
+    def net_kettle_deadspace(self):
+        # If hops in kettle deadspace
+        result = self.kettle_dead_space - self.hop_water_loss
+        return float(max(0, result)) # No deadspace if its all filled with hop trub)
+
+        # Else hops in bag or removed
+        return 0
+
+    @property
+    def kettle_hose_loss(self):
+        return .25 # TODO
+
+    @property
+    def kettle_dead_space(self):
+        return .25 # TODO
+
+    @property
+    def boil_off_gph(self):
+        return .8 # TODO
+
+    @property
+    def ibu_tinseth(self):
+        return  sum([x.ibu_tinseth for x in self.hops])
+
+    @property
+    def srm(self):
+        color_total = sum([x.srm for x in self.fermentables])
+        return 1.4922*(color_total**0.6859)
+
+    @property
+    def srm_hex(self):
+        SRM_HEX = {
+            1: 'F3F993',2: 'F5F75C',3: 'F6F513',4: 'EAE615',5: 'E0D01B',
+            6: 'D5BC26',7: 'CDAA37',8: 'C1963C',9: 'BE8C3A',10: 'BE823A',
+            11: 'C17A37',12: 'BF7138',13: 'BC6733',14: 'B26033',15: 'A85839',
+            16: '985336',17: '8D4C32',18: '7C452D',19: '6B3A1E',20: '5D341A',
+            21: '4E2A0C',22: '4A2727',23: '361F1B',24: '261716',25: '231716',
+            26: '19100F',27: '16100F',28: '120D0C',29: '100B0A',30: '050B0A'
+        }
+
+        return '#{}'.format(SRM_HEX[int(self.srm)])
+
+
     def __str__(self):
         return self.name
 
@@ -97,6 +188,7 @@ class Fermentable(CustomIngredient):
     types = {
         1: 'Grain',
         2: 'Adjunct',
+        3: 'Sugar'
     }
 
     grain_category = models.IntegerField(choices=categories, default=1)
@@ -119,6 +211,10 @@ class RecipeFermentable(CustomModel):
     fermentable = models.ForeignKey(Fermentable, on_delete=models.CASCADE)
     quantity = models.DecimalField(max_digits=6, decimal_places=4)
 
+    @property
+    def srm(self):
+        return round(float(self.fermentable.lovibond) * float(self.quantity) / self.recipe.final_volume, 1)
+
 class Hop(CustomIngredient):
     uses = {
         1: 'Bittering',
@@ -155,6 +251,25 @@ class RecipeHop(CustomModel):
     time = models.IntegerField(default=60, validators=[MinValueValidator(0)])
     use = models.IntegerField(choices=uses, default=1)
 
+    @property
+    def ibu_tinseth(self):
+        type_bonus = {
+            1: 1.1, # Pellet
+            2: 1.0, # Leaf
+            3: 1.1, # Cryo
+            4: 1.4, # CO2 Extract
+        }
+
+        ibu = 0
+
+        average_wort_sg = (self.recipe.pre_boil_sg/1000 + (self.recipe.original_sg-1)) / 2
+        if self.use == 1:
+            conc = ((float(self.hop.alpha) / 100) * float(self.quantity)) * 7490 / self.recipe.final_volume
+            util = (type_bonus[self.hop.hop_type] * 1.65 * (0.000125**average_wort_sg)) * ((1-2.71828182845904**(-0.04 * self.time))/4.15)
+            ibu = conc * util
+
+        return float(ibu)
+
 class Misc(CustomIngredient):
     uses = {
         1: 'Mash',