def compute_empirical_efficiency(self, collected_volume, measured_og):
""" returns the empirical efficiency in % based on collected volume (L),
and measured OG (specific gravity). In order to estimate your brewhouse efficiency on that particular recipe.. """
pot_gravity = self._get_potential_gravity(l_to_gal(collected_volume))
efficiency = 0
if pot_gravity > 0:
efficiency = (measured_og - 1.) / pot_gravity
return int(efficiency * 100)
def _get_potential_gravity(self, batch_size):
points = []
if not batch_size:
batch_size = l_to_gal(self.batch_size)
for grain in self.recipemalt_set.all():
pounds = kg_to_lb(float(grain.amount))
gravity = float(grain.potential_gravity - 1) * 1000.
points.append(float(pounds) * float(gravity))
return (float(sum(points)) / float(batch_size)) / 1000.
def get_srm(self):
cache_key = "%s_get_srm" % self.cache_key
recipe_srm = cache.get(cache_key)
if recipe_srm is None:
grain_srm = []
batch_size = l_to_gal(float(self.batch_size))
for grain in self.recipemalt_set.all():
pounds = kg_to_lb(float(grain.amount))
lovibond = ebc_to_srm(float(grain.color))
grain_srm.append(float(lovibond * pounds) / float(batch_size))
recipe_mcu = float(sum(grain_srm))
recipe_srm = 1.4922 * (recipe_mcu**0.6859)
cache.set(cache_key, recipe_srm, 60 * 15)
return float(recipe_srm)
def ibu(self):
if self.usage == "dryhop":
return 0
elif not self.boil_time:
return 0
volume = float(l_to_gal(self.recipe.batch_size))
gravity = float(self.recipe.get_original_gravity()) - 1
alpha = float(float(self.acid_alpha) / 100)
mass = float(g_to_oz(self.amount))
time = float(self.boil_time)
mgperl = alpha * mass * 7490 / volume
util = 1.65 * (math.pow(0.000125,
gravity)) * (1 - math.exp(-0.04 * time)) / 4.15
ibu = mgperl * util
if self.form == "pellets":
ibu += ibu * 0.105
if self.usage == "firsthop":
ibu += ibu * 0.105
return ibu
def initial_heat(self):
# TODO :
# Why this doesn't work properly
# with total grain weight ??
# Equation doc : http://www.byo.com/stories/techniques/article/indices/45-mashing/631-feel-the-mash-heat
Hm = 0.3822 # heat capacity of malt
Hw = 1.0 # heat capacity of water
Tmt = 74 # temperature of dry malt
Tma = float(c_to_f(float(
self.temperature))) # temperature of mash step
M = float(kg_to_lb(
self.recipe.get_total_grain())) # weight of malt in lbs
if M == 0.0:
M = 1.
W = float(float(l_to_gal(self.water_added)) * M) # weight of water
if W == 0:
temp = self.temperature
else:
temp = f_to_c(((M * Hm * (Tma - Tmt)) / (W * Hw)) + Tma)
return temp
def get_preboil_gravity(self):
batch_size = l_to_gal(
float(self.batch_size) + float(self.water_boiloff()) +
float(self.boiler_tun_deadspace))
return self.get_original_gravity(cache_key="_pbg",
batch_size=batch_size)