Hapa's Brewing Company

Brewing

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A Delicate Balancing Act

Warning: Science content below!

The beer has been brewed, it’s been carbonated, and the kegerator has been made.  All that’s left is to pour yourself a glass.  It seems like a simple thing: pull the tap handle and have beer flow into a glass with a perfect frothy head.  However, like many things, this is easier said than done.  For beer to pour properly from the tap, the draft system must be balanced.

There are several factors that need to be considered when balancing a system.  All of these factors ultimately affect the way beer will pour out of the tap:

  • The temperature of the beer
  • The beer’s level of carbonation
  • The CO2 pressure kept in the keg
  • The length and diameter of the beer line
  • The height the beer must flow to reach the faucet

The first step in balancing a draft system is to determine the level of carbonation for the beer.  The level of carbonation depends on the style of beer, but is ultimately based on opinion.  As mentioned in The Great Carbonation Debate, beer is force carbonated by first cooling it and then adding CO2 at pressure. Click here to view a chart that outlines the level of carbonation achieved with a given temperature and pressure and the recommended volumes of CO2 for a given style.

The pressure needed to properly carbonate beer is an important number.  Not only is this pressure keeping the beer bubbly, but it is also going to be used to force beer up the lines and out the faucet.  The concept behind balancing a draft system is to drop nearly all of that pressure in the time it takes for the beer to travel from the keg to the faucet leaving just enough to get the beer to flow out.

There are several forces that work against the pressure exerted by the CO2 in the keg.  These are gravity, the length of the beer line, and the resistance of the beer line.  We can create a formula that describes how the pressure from the keg (measured in PSI) will be affected by these factors:

P = Pressure of CO2 in keg (in PSI)
H = Height from middle of keg to faucet (in feet)
A = Pressure lost per foot of height due to gravity (in PSI/foot)
L = Length of beer line (in feet)
R = Pressure lost per foot of beer line due to resistance (in PSI/foot)

Essentially what we are doing in this formula is subtracting PSI lost due to gravity and the PSI lost due to the resistance of the beer line from the pressure in the keg.  If the net of this equation was zero, there would not be enough pressure to get beer to flow from the faucet.  There needs to be at least 1 PSI left to get beer to flow, so we set the equation equal to one:

Time to fill in some of these numbers: Gravity accounts for a .5 decrease in PSI per vertical foot the beer must travel and in my system the height is 2.75 feet.  The resistance of the beer line depends on its inside diameter.  For 3/16″ beer line (which is what I use) we will lose an average of 1.8 PSI per foot.  The pressure of my keg is 9 PSI which at 38 degrees gives me a carbonation level of 2.3 volumes.  Plugging these numbers into my equation I can figure out how long my beer line should be to have a smooth pour.

Solving for L (assuming my math is correct), I get 3.7 feet of beer line is needed.  The tower came with 5 feet of beer line, so I just cut away what I don’t and reattach the liquid out ball lock disconnect.  Just in time too, after all that math and science, I need a beer!

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The Great Carbonation Debate

The final step in brewing beer (aside from drinking it!) is to carbonate it.  You would be hard pressed to find someone who enjoys a flat beer.  Carbonation gives beer a light and refreshing feel in the mouth when consumed and also enhances flavors and aromas.  The questions is: how is beer carbonated?

As I eluded to in The Final Countdown, there are two ways to carbonate beer: force carbonation and natural carbonation.  Both have their advantages and disadvantages:

Natural Carbonation

To naturally carbonate beer, a small amount of sugar (called priming sugar) is added to the beer after fermentation has completed.  The beer is then put into bottles, growlers, kegs, etc. and sealed.  Residual yeast will then ferment this sugar and produce alcohol and CO2.  Because the vessel in which the beer is being held is sealed, this CO2 dissolves into the liquid thereby carbonating the beer.

Advantages:

  • Some people say that natural carbonation results is a thicker head, smaller bubbles, and more lacing (lacing is the ringing of foam around a glass that is left when the head dissipates.  It is considered a good thing.)
  • It requires less equipment than force carbonating
  • It’s traditional and all natural

Disadvantages:

  • It takes longer to carbonate your beer.  Beer that has been naturally carbonated needs an additional 2-4 week for fermentation and conditioning to take place
  • If too much sugar is added, beer can be over-carbonated or bottles can explode
  • More yeast will settle on the bottom of the bottles which doesn’t look pretty

Force Carbonation

To force carbonate beer, it is transferred to a keg where it is chilled.  CO2 is then pumped into the keg and kept at pressure.  Over the course of a few days this CO2 will dissolve into the beer carbonating it.

Advantages:

  • It takes much less time to carbonate beer; only 3-7 days
  • Results in cleaner looking beer
  • Takes guess work out of adding priming sugar
  • Doesn’t result in added yeast flavors in the final product

Disadvantages

  • It requires expensive equipment
  • Can result in a head that is less billowy and has worse lacing
  • Deviates from the all natural brewing process

 In the end how beer is carbonated is a matter of personal preference.  I happen to have all the equipment I need for force carbonation, and combined with my lack of patience, results in my preference of force carbonating beer.

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The Final Countdown

This weekend was Halloween which meant it was time for candy, costumes, and of course beer!  Between some great football games and the World Series, I was able to transfer the Brown Ale to the keg.  The process is very similar to the one used when moving the beer to the secondary fermenter; using an auto siphon to carefully transfer the beer. 

        
Glass carboy and 3 gallon keg                                 Siphoning beer to the keg

The next step is carbonating the beer.  There are two methods for carbonating beer: natural vs. forced.  The difference / advantages / disadvantages of these two methods will be discussed in a future posting, but because I have a draft system and because I don’t have enough patience to wait for natural carbonation, I have chosen to force carbonate my Brown Ale.

The process of force carbonation begins with cooling the beer down as gasses dissolve easier in liquids at lower temperatures.  Once the beer has been cooled, CO2 is pumped into the keg at kept at a pressure of around 10-12psi.  Over the course of a couple days, the CO2 will dissolve into the beer and an equilibrium will be reached.  At that point the beer is ready to be enjoyed!


Keg at CO2 tank in the fridge

As you can see, I keep my draft system in a mini fridge.  This set up works for now, but I’m planning on coverting the fridge to a kegorator… stay tuned!

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Fermentation: Fun Enough to do Twice!

It has been a week since the Brown Ale went into the fermenter which means it’s time to transfer the beer to the secondary fermenter.  I use a glass carboy for secondary fermentation.


Glass carboy and siphon

Secondary fermentation is not a necessary step in the brewing process, but it definitely has some advantages.  During primary fermentation dead yeast, proteins, and other particles like bits of hops settle to the bottom of the fermenter forming a layer call the trub.  Separating the beer from this layer prevents unwanted flavors from being imparted into our beer.  Allowing all these particles to settle out will also result in a clearer final product. 

When transferring beer from the primary to secondary fermenter, it is important to minimize the beer’s exposure to air.  Extended exposure to air or excessive slashing can lead to oxidation of the beer.  Oxidation can lead to off flavors or a stall in the fermentation process.  To minimize slashing and exposure to air, I use an auto siphon and to control the flow of beer I pinch the line with a clamp.


Siphoning beer

After transferring all the beer it is important that the carboy go back into a dark area with a stable temperature of 65-75 degrees.


Full carboy

One more week to allow the beer to condition and clarify.  Let the countdown begin!

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Ales vs. Lagers

Beer comes in a wide variety of styles, colors, and tastes.  Some are full bodied and have strong hop flavors, while others come in a can with a wide mouth and vent to help it pour down your gullet faster.  What is it that distinguishes one beer from another?  At the highest level, differences in beer styles come from the strain of yeast that is used during fermentation

 

There are two kinds of yeast used in beer making: ale and lager.  There are several differences between these yeast varieties that impact the brewing process and final product.

 

Temperature:

Lager yeast prefers a lower temperature while it ferments sugars to alcohol.  If you’ve ever heard the slogan “Frost Brewed,” you’re drinking a beer made using lager yeast and are probably drinking out of a can with blue mountains.


 

Time:

The lower temperature of the fermentation process means it takes longer to complete.  Where primary fermentation for an ale might be one week, a lager can take up to three.  Lager needs a longer time to condition as the yeast produces more sulfur based compounds.  These compounds can impart a bad smell and taste to the beer and need time to vent off and be broken down by the yeast.

 

Taste:

Lagers are characterized by their clean, crisp taste.  Some might call it “drinkability.”  This is opposed to ales whose fruit flavors and full bodied feel are a result of warmer fermentation temperatures and increased bittering hop usage.

 

Top vs. Bottom Fermenting:

Lager yeast is bottom fermenting, meaning it sits at the bottom of a fermenter during the brewing process.  Ales yeast do just the opposite, fermenting sugars at the top of the fermenter. 


Fermentation Tanks
 

Lager is the America’s most popular style of beer.  You are very familiar with American Lagers as they are produced of the most famous names in beer including Budweiser, Coors, and Miller.  You have undoubtedly enjoyed a lager… or ten… while watching football on Sundays.  Now you will able to impress your friends with an Alex Trebek like knowledge of beer!

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It’s Not Me, It’s Brew

After discussing the basics of brewing beer, it’s time to put our knowledge to use.  Yesterday, I paid a visit to San Francisco’s iconic homebrew shop, San Francisco Brew Craft, with the intention of purchasing all the ingredients I would need to brew a batch. 


San Francisco Brew Craft

After a brief deliberation I decided to make an English Brown Ale.  This is one of my favorite styles of beer; if you’ve ever had New Castle, you’ve had an English Brown Ale.  Characteristics of this style of beer include a dark brown or amber color and a nutty and/or malty flavor.  They also like long walks on the beach, candle lit dinners, and romantic comedies.  Often, Brown Ales will have hints of chocolate and burnt toast flavors.  These dark colors and distinct flavor profiles are due, in large part, to the use of Crystal malts

It had been awhile since my last brewing session, so I decided to knock off some rust with a malt extract brew.  Malt extract is made by boiling down wort to a syrup like consistency and allows brewers to remove mash from the brewing process.  I have mixed feelings about extract brewing.  The mashing process is a major component of brewing and removing it always leaves me feeling like I’ve cheated.  I’m sure Mr. Budweiser and Mr. Coors never brewed with extract!  I laid out all my brewing equipment before getting started:


Specialty grains, extract, brew pot, wort chiller, fermenter

The first step for this brew was to steep the specialty grains which, for this recipe, were Crystal malt, oat flakes, and chocolate malt.  Steeping grains is essentially like an abbreviated, small scale mash.  As such, it is important that the water in which we soak the grains is at the proper temperature to activate the starch converting enzymes.  The grains are place in cheese cloth and dipped in the brew pot just like a giant tea bag. 

        
Steeping specialty grains                                                Wort after steeping

Our next step in the brew is to add the malt extract and begin the boil.  I used 6.5 pounds of extract.


Adding malt extract

When the wort begins to boil proteins from the grain being to coagulate and form what’s known as the “hot break.”  The hot break takes the form of a layer of foam on the surface of the liquid.  As more protein clumps together they will eventually settle to the bottom of the pot and the foam will dissipate.  After the hot break we add our bittering hops.  I used Kent Golding hops in pellet form for this brew.

        
“Hot break”                                                                    Pellet hops

The wort boils for an hour with additional hop additions at thirty minutes and ten minutes.  These additions help add a nice aroma to the finished beer.

After the boil, the wort needs to be cooled down quickly to reduce the chances of contamination as well as induce additional proteins to precipitate.  To chill my wort quickly I used a copper immersion chiller.  Cool water is run through the copper tubing that absorbs heat from the wort.


Chilling the wort

After cooling the wort to 75-80 degrees, we transfer it to the fermenter and pitch the yeast.  I used Burton Ale yeast in liquid form for this brew.  Secure the lid on the fermenter, insert the airlock, and stow in a an area with a stable temperature of 65-75 degrees that does not receive any sunlight.  Exposure to direct sunlight can kill a vampire.  It can also skunk your beer.

        
Pitching the yeast                                                       See you next week

I checked on this batch today, and am getting some active fermentation as we speak.  After one week of fermentation I will transfer the beer to a secondary fermenter for an additional week before kegging / bottling.  The hardest part of brewing is not all the chemistry or biology, it’s the waiting!

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Welcome to Brewing 101

I know what you’re thinking, the name Hapa’s Brewing Company implies a devilishly good looking founder, and you would be correct.  You might also be thinking that the name implies something concerning the brewing of beer, and again you would be correct.  Hapa’s Brewing Company is devoted to the art and craft of brewing beer.  However, we are also equally devoted to the creation of delicious food to enjoy with that beer. 

Thus far the subject matter of our blogs has been focused on food.  Well it’s time to get back to our roots and talk about beer.  If you’re like me, you made the natural assumption that beer is created by collecting the tears of leprechauns and adding a dash of witchcraft.  This is surprisingly far from the truth.  The process of making beer combines equal parts science (biology and chemistry) and culinary arts. 

 
How then does one make beer?  We begin the process here:


Here is a barley field.  It turns out the beer is made from barley and not the sweet delicious tears of leprechauns.  After the barley is harvested is it soaked in water, dried, and allowed to germinate.  Once the seeds have begun to sprout, the germination process is cut short by baking the barley.  During the germinations process enzymes are triggered that will convert the starches in the seeds into simpler sugars.  It is these sugars that will be fermented during the brewing process.

 

The next phase in brewing is to extract those sugars.  This process is called mashing.  During the mash the ground malted barley is soaked in hot water.  The hot water activates the enzymes in the grain which after some blah, blah, blah, science, science, science convert the starches into sugar.


Mash tun


The hot sugary water is then separated from the grain in a process called lautering.  At this point the water is called wort (pronounced wert).  The wort must now be boiled.  The boiling of wort accomplished several things.  First, the hot temperature of the boil will sterilize the sugary solution we have created (a perfect environment for microorganisms).  Secondly, the boiling process will cause the natural proteins in the grain to coagulate allowing them to later settle out.  Thirdly, we will be adding hops during the boil.  Hop oils only become soluble at high temperatures which is necessary to impart the bitter flavor that we enjoy in beer.


Hops

After the boil, the hot wort must then be chilled before yeast can be added.  When you think of fungi, you don’t necessarily think of an organism that is very particular about where it lives. However, yeast is very picky about where it thrives and perpetuates and will only flourish at certain temperatures.  Wort right after the boil is too hot. 

The process of adding yeast is called pitching the yeast and is the next step in brewing beer.  Yeast is an interesting organism in that it can respire both with oxygen (aerobic) and without (anaerobic).  When yeast is exposed to an oxygen deprived environment it is able to produce energy by converting sugar into carbon dioxide and ethanol (a.k.a. fire water); a process called fermentation.  Yeast may be a microscopic organism, but it truly does a lot of the heavy lifting in the brewing process.


Yeast cells

The fermentation process takes approximately two weeks.  Eventually yeast cells will clump together in a process known as flocculation.  These clumps fall to the bottom of the fermentation tank allowing us to siphon off our freshly made beer.  The beer must then be bottle or kegged and carbonated.  Beer can be naturally carbonated by adding a small amount of sugar and sealing the beer in a bottle.  The residual yeast will ferment this sugar creating carbon dioxide which will dissolve in the bottle beer.  Likewise, we can artificially carbonate beer by sealing it in a keg and pumping in pressurized carbon dioxide thereby dissolving the gas into the beer.

The last step in brewing is everyone’s favorite:

 

Homebrewing is a fun and ultimately rewarding hobby.  It is also easy enough for anyone to do.  Check out the complete homebrewing kit in our “Featured Products” section in the right hand navigation.  Happy brewing!