Transcript Welcome to the 1st MLBA Meeting!

Welcome to the April 7th
MLBA Meeting!
Please find the register and sign in.
Please also feel free to order food and a beer.
The Importance of a Good Boil
and How it Affects Your Beer
Or how to make something simple
really complicated
Alex Crowe
What we will cover today
• What is happening in the boiling stage
• Strategies to capitalize on desirable events
and minimize undesirable events
What we will cover in detail in a
separate talk
• Hop extraction and isomerization
• Calculating bitterness
• hopping strategies
What are we accomplishing in the
boil?
At the boil, the bitterness, clarity, stability, and
some of the color of the beer are established.
The Quick Answer
• Heat wort as quickly as possible without
burning.
• A good rolling boil for at least one hour with
good ventilation is best.
• Cool wort as quickly as possible.
• Add hops as appropriate for the style or your
taste: early for bitterness and late for flavor.
A Rolling Boil
From: www.picasaweb.google.com/lh/photo/
What happens during the boil?
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Enzyme inactivation
The Hot Break
Pasteurization
Evaporation of desirable volatile aromas
Generation of undesirable volatile flavors
Hop oil isomerization and extraction
Concentration of the wort
Caramelization
The Cold break
Enzyme inactivation
Your Goal: End the reactions of the mash
• Wort enzymes, if allowed to continue to function,
will cause the body of the beer to decrease.
• Enzymes are proteins, many proteins will denature
(become inactivated) at the hot break.
• Boiling the wort ends all reactions from the mash.
• You want to get to a boil quickly and get a good hot
break.
The Hot Break
Your Goal: Clarify and stabilize the beer
• When a boil is reached
there is a sudden foaming
up of the wort – this is the
“Hot Break”.
• Proteins denature and fall
out of solution when boiled.
://www.homemade-chinese-soups.com/image-files/eggdrop-soup.gif&imgrefurl=
• A good hot break will make a clear beer!
• Adding Irish Moss will bind proteins and make the hot
break more effective.
• Sediments are called trub (Ger. = mud).
Pasteurization
Goal: Kill microorganisms
• Heat Kills!
• The higher the temp the
faster the kill rate.
• One Pasteurization Unit (PU)
is 1 min at 142⁰F (60⁰C).
• Each microorganism has a
different lethal temperature.
TMI corner Calculating kill rates
PU= Σ (L(T) * Δt/tref )
L(T) =10 (Δt/z)
from://www.nzifst.org.nz/unitoperations/
unopsassets/fig6-7.gif
Evaporation of Undesirable Aromas
Your Goal: Remove DMS (canned corn flavor)
• Dimethyl Sulfide (DMS) is created in the boil (heat
causes a nutrient precursor to break down).
• You want a very rapid boil with good ventilation to
cause this compound to evaporate. A slow boil or
poor ventilation will not.
TMI corner
S-Methyl Methionine is
important for DNA
synthesis in the barley,
but is heat labile in the
kettle
We will now pause for flavor
identification
Dimethyl Sulfide
DMS
Low levels taste like canned corn, higher levels
like olive brine and very high levels like
spoiled oysters.
Evaporation of Desirable Aromas
Your Goal: Minimize the loss of desirable aromas
• Any aroma is a compound which likes to evaporate.
• Good hop floral notes evaporate rapidly in the boil.
• If you want a big hop aroma, add hops late in the boil
(or after the boil).
Hop oil extraction and isomerization
Your Goal: Extract flavor and create bitterness.
• Hop oils are not very water soluble.
• Longer boiling times give more extraction.
• Heat changes structure of hop oils (isomerization) to
make them bitter.
• If you want more bitterness add hops early in the
boil.
TMI corner
(% alpha acids)x(% utilization)x(wt. of hops in ounces)
IBU (ppm alpha acids) =
(volume in gallons)x( 1.33 conversion factor)
Percent utilization depends on the amount of time the hops are boiled and the sugar
concentration in the wort
Calculators which account for utilization can be found at www.rooftopbrew.net/ibu.php
Concentration of the Wort
Goal: Reach or maintain your target specific gravity
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Water evaporates when boiled.
You want to account for this when starting boil.
I like to calibrate my kettle with a measuring rod.
In general on my system 6 gals boils down to 4.8 gal
in 1hr - that’s 20% per hour!!!
• You can start with more water or add water late in
the boil to compensate for losses.
Caramelization
Your Goal: Limit or enhance caramel flavor
and brown color of the beer
• Sugar, water, and amino acids when heated form
brown flavorful compounds.
• Longer boil or hot spots cause this to be more rapid.
• For a 1 hr boil on a stovetop this is minimal.
TMI corner
Caramels are mixtures of colored colloids and breakdown
products caused by heating sugars (eg candy making) and can
taste like caramel or burnt sugar (treacle). Melanoidins are
brown compounds which form between amino acids and
sugars (eg toasting bread) and can taste like nuts, breadcrust
or toasty. Both reactions are complicated and hard to control.
Whirlpooling
Your Goal: Remove solids to control beer flavor
• Creating a vortex in a liquid
causes solids to collect in the
center.
• Easy way to remove solids.
• Denatured proteins are bitter and
cause haze.
• Hops not removed will continue
to add bitterness to the beer.
• Give wort a spin, let it settle for
10-15 mins, and siphon from the
side into the fermenter.
From:
www.braukaiser.com/wiki/images/b/bf/
Whirlpool_dynamics.gif&imgrefurl_
The Cold Break
Your Goal: Rapid cooling to stop generation of DMS
• When the boil is finished DMS is
still being generated but not
evaporated.
• Fast cooling also helps trap
proteins which cause haze in a
denatured state (“Cold Break”).
• Use a wort chiller, or dilute wort
into cold water.
www.rebelbrewer.com/shoppingcart/produ
ct_images/d/wortchiller
The Quick Answer
• Heat wort as quickly as possible without
burning.
• A good rolling boil for at least one hour with
good ventilation is best.
• Cool wort as quickly as possible.
• Add hops as appropriate for the style or your
taste: early for bitterness and late for flavor.
Equipment Corner
Belgian Candied Sugar
Wort Chiller Project???
If anyone is interested in building a wort chiller
please let us know. We would like to make a
project video on this subject.
Please see Matthew Pieters or Jeremy Johnson.
Open Tasting Time
If you have not done so please label and sticker
your beer.
Enjoy some great beer!