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?

• 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

• 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.

Your Goal: End the reactions of the mash

The Hot Break

• 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.

• 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).

://www.homemade-chinese-soups.com/image-files/egg-drop-soup.gif&imgrefurl=

Your Goal: Clarify and stabilize the beer

Pasteurization

• 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.

from://www.nzifst.org.nz/unitoperations/unopsassets/fig6-7.gif

PU= Σ (L(T) * Δt/tref )

L(T) =10 (Δt/z)

Goal: Kill microorganisms

TMI corner Calculating kill rates

Evaporation of Undesirable Aromas

• 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.

Your Goal: Remove DMS (canned corn flavor)

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 SulfideDMS

Low levels taste like canned corn, higher levels like olive brine and very high levels like spoiled oysters.

Evaporation 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).

Your Goal: Minimize the loss of desirable aromas

Hop oil extraction and isomerization

• 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.

Your Goal: Extract flavor and create bitterness.

TMI corner (% alpha acids)x(% utilization)x(wt. of hops in ounces)

(volume in gallons)x( 1.33 conversion factor)IBU (ppm alpha acids) =

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

• 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.

Goal: Reach or maintain your target specific gravity

Caramelization

• 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.

Your Goal: Limit or enhance caramel flavor and brown color of the beer

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

• 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_

Your Goal: Remove solids to control beer flavor

The Cold Break

• 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/product_images/d/wortchiller

Your Goal: Rapid cooling to stop generation of DMS

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!