Brewing Ingredients and Process

1 http://www.grains.org/buyingselling/barley

2 http://nutritiondata.self.com/facts/cereal-grains-and-pasta/5687/2

Beer is much more than the sum of its ingredients. Nevertheless, the type of ingredients that make up beer are fundamental predictors of flavor and quality. Despite the complexity of flavors and aromas in beer, the qualities of beer are ultimately influenced by 4 different ingredients: malt, yeast, hops, and water. Despite the importance of the ingredients used, beer is much more than the sum of its ingredients. The process of brewing is designed to bring the most out of the ingredients used in beer. The general process of brewing hasn’t changed very much for centuries. The only thing that has changed greatly in the past 300 years is the quantity and quality of the beer being produced. Grains for Beer As mentioned previously, malt is essentially germinated grain. All grains contain the basic parts below:

The germ is where the plant embryo is contained. As well as being absolutely essential for the malting process, the germ contains vitamins B and E.

The endosperm is important because it contains the carbohydrates, which are the ultimate source of alcohol in beer. Additionally, storage proteins (gluten in wheat, barley, and rye) contained in the endosperm contribute to head and mouthfeel of beer.

Bran, while of no direct use in malting or alcoholic fermentation, is nevertheless important because it acts as a filter during the brewing process as well. Additionally, the bran contains B vitamins. As stated previously, all types of grains include these parts within them. Because of that, many types of grains are suitable for brewing. Some grains make for better beers than others, though! Barley Barley (Hordeum vulgare)is the favored and most-used grain for beer. Barley is preferred for several reasons:

1) Ripens faster than wheat 2) Germinates rapidly 3) Hardy and salt tolerant

4) Husk is helpful in filtering during brewing

In the US, barley is primarily grown in North Dakota, Montana, Wyoming, Idaho, and Washington state. There are 2 main varieties of barley used in brewing: 2 row and 6 row:

2 row barley has the widest use while 6 row barley is used by the largest breweries. Below are the important differences (besides grain arrangement) between 2 and 6 row barley:

Barley in the USA

The map 1 below shows where most of the barley in the US is grown. Given the geographic distribution, what can you say

about the climate that barley prefers to grow in?

2 row 6 row

row

Diastatic power is the only major difference between the 2 barley varieties. 6 row barley has a greater diastatic power, which means that the malting process (where starch is converted to fermentable sugars) happens more quickly. This is a good thing if your goal is to make product as quickly as possible. Non-barley grains There are plenty of other grains used in brewing:

An adjunct is a source of starch or sugar used to supplement the main grain. The purpose of adjuncts is for:

1) Foam stability 2) Added nutritional value 3) Decrease in haze defects (haziness in beer caused by protein becoming insoluble in the beer in cold

temperatures) 4) Additional flavors

Corn and Beer Cost

Corn is definitely king of adjuncts in American brewing. Up to 50% of the grain used in adjunct lagers can be corn! Corn is mostly used by large brewers in order to produce a more consistent product. Here’s how the 2 grains stack up 2 :

Corn Barley

Total Fat 4.7 g

7%

2.3 g

3%

Saturated fat 0.7 g

3%

0.5 g

2%

Polyunsaturated fat 2.2 g 1.1 g

Monounsaturated fat 1.3 g 0.3 g

Sodium 35 mg 1%

12 mg 0%

Potassium 287 mg

8%

452 mg

12%

Total Carbohydrate 74 g

24%

73 g

24%

Protein 9 g

18%

12 g

24%

Fat isn’t really a big concern in the quality of beer. What is a big concern is protein. Excessive protein causes haze

defects, so one strategy to have a product that is more consistent in color and clarity is to use a grain with less

protein. Corn definitely fits the bill here.

Sorghum beers are often the types of beers that are most – often touted as “gluten free”, even though the arguably more common rice beers can make the same claim.

Yeast

Brettanomyces (sometimes called “Brett” by American winemakers) and Candida spp. were often the cause of the “spontaneously – formed” beers that were most often made in ancient times. Both of the wild yeast have lower alcohol tolerances than Saccharomyces does. Yeast cells were 1st visualized in 1680 by Anton van Leeuwenhoek, who used a single lens microscope to see the cells. It is unlikely that Anton van Leeuwenhoek thought they were living organisms. The establishment of yeast as a living organism responsible for alcoholic fermentation was the result of the work of Louis Pasteur in the 19th century. Pasteur disproved the idea of spontaneous generation of bacteria and yeast in his famous swan-necked flask experiments, which are diagrammed below:

Growth media placed in a flask with a impeded neck (a “swan necked” flask) was boiled to sterilize the media. Over time, no bacteria or yeast growth was detected. If the neck was broken, freeing a path to the media, the media became contaminated with yeast and bacteria growth. Louis Pasteur also illustrated an important aspect of yeast growth by showing that by bubbling oxygen into yeast broth, growth could be increased but fermentation would be inhibited. This so-called Pasteur Effect is used to great effect in brewing in order to increase yeast cell numbers prior to fermentation. There are 2 main species of yeast used in brewing: Saccharomyces cerevisiae and Saccharomyes carlsbergensis.

The most important thing about Saccharomyces cerevisiae (“top-fermenting yeast”) is that it is used to make types of beers called ales.

S. carlsbergensis, a type of “bottom-fermenting yeast”, is sometimes called Saccharomyces pastorianus nowadays. This type of yeast is used to make lagers. Lagers are traditionally made in cooler countries that have temperature conditions that aren’t ideal for ale brewing. S. carlsbergensis has the benefit of being more cold tolerant than S. cerevisiae. The cold tolerance is important when the beer is stored (“lagered”) in cold cellars during the summer. Hops Hops are the female flowers of the hop plant (Humulus lupulus). Hops are used chiefly as flavoring agents because they provide bitter and tangy flavors to offset malt sweetness. The oils contained in hops also have antimicrobial qualities, which means they can stop the growth of microorganisms or kill them. The essential oils responsile for the antimicrobial qualities of the hop are found with other flavoring agents inside small yellow glands in the flowers called lupulin glands. A closeup of the lupulin glands is shown below:

The primary bittering agents in the lupulin glands are called alpha acids, the most prevalent of which is humulone. Humulone is converted to a compound called isohumulone during heating, which is more soluble in water than humulone is. Isohumulone reacts with light (in particular, UV radiation in light) to form “skunky” tasting sulfur compounds, so it is important to limit the exposure of beer to light (use dark bottles or store the beer in a dark place) to preserve the quality of beer and prevent it from skunking! There are many different varieties of hops, and each variety has different levels of alpha acids (and therefore bitterness) as well as other types of flavors. Hops typically contain some degree of the following types of flavors: spicy, floral, fruity, citrus, herbal, earthy, and evergreen. Below is a graphic showing the distribution of all these flavors in several hops varieties:

Cascade hops are the most popular variety in the US. Other varieties, like Simcoe and Citra, are proprietary and can only be used by licensed breweries. As far as bitterness is concerned, this is how several varieties of hops compare:

More alpha acids = more bitter! Water Beer is mostly water, and the quality of water is important to the quality of the beer. Water contains several different types of ions that are important in brewing:

– Calcium – lowers pH during mashing, which could affect amylase activity – Carbonate/bicarbonate – determine acidity, which is important to enzyme functioning – Sodium – contributes to the body and mouthfeel of beer, too much sodium is not good for the taste – Sulfate – brings out the bitterness of hops – Magnesium – important micronutrient for yeast

Overview of Brewing On the surface, brewing looks like a complex process. Just see how it’s diagrammed below:

It becomes easier to take in when you group up all of these unit operations into broad categories:

1) Harvesting 2) Malting

3) Brewing 4) Fermenting 5) Maturation 6) Finishing

Harvesting When barley (or some other grain) is harvested, it is traditionally allowed to dry to < 18% moisture content in order to reduce incidence of fungal contamination and to increase the concentration of sugars and starches. After combining (harvesting plants and separating the grain from the other parts of the plant), the grain is dried and typically sold at selling points, which store the grain and sell in to companies that order it. Care must be taken to control for broken or otherwise damaged kernels that are unable to germinate, as grain in this condition is not suitable for brewing. Malting The malting process is necessary in brewing because it produces and frees up sugars in the barley kernels for the yeast to ferment. The enzyme amylase, produced by germinating grain kernels, hydrolyzes the amylose in the endosperm to a type of disaccharide called maltose:

Malting has 3 distinct steps: steeping, germinating, and kilning

1) Steeping – Steeping involves soaking grain kernels in water several times or for several hours. The purpose of steeping grains is two – fold. Steeping acts as a germination trigger. Steeping also removes some tannins (cause astringent mouthfeel in beer and wine), acid (could interfere with fermentation), and protein (cause haze defects).

2) Germinating – Germinating means to allow the grain to sprout for several days. When grains germinate, enzymes such as amylase and protease are activated within the germ. Germination times vary by grain, and barley is usually allowed to germinate for 4 – 5 days after steeping the kernels. Germination is considered done when the sprouts are ¾ of the kernel length. Here’s an idea of how germination progresses in barley:

At this point, the germinated kernels are called green malt.

Too early Just right

Too late

3) Kilning – Kilning is the first point in the brewing process that will ultimately determine the style and quality of beer you end up with. Kilning involves baking the green malt in an oven in order to both stop the malt from germinating and to impart colors and flavors to the malt. After this point, malt is generally classified by its color, and the darker the color of a malt, the longer it has been kilned.

Before the next phase of beer production, the kilned malt is passed through a mill (usually a roller mill, a small one is pictured below):

Milling the malt with a roller mill will essentially squash and crack the grains. This roughens up the malt and allows the grist, or solid parts of the milled grain, to perform better in brewing. Brewing The word “brewing” technically refers to the steps of beer production after malting but before fermentation. In practice, brewing has been used to refer to the entire process of beer production. The actual brewing process is

Kilned Malts and their Roles

Beers aren’t made from just one type of malt. In the brewing phase of beer production, a mixture of malts (depending

on the style of beer desired) is used. The mixture of malts used is often referred to as the “grain bill” of brewing, and the

majority of the malts used in the grain bill are base (a.k.a. pale) malts. That’s because base malts contain the greatest

diastatic power. Here’s a rundown of common malts:

Type Description Used in

Base malts (a.k.a. pale malts)

Regular, lightly kilned malt that makes up the majority of the grain bill. Contains most of the diastatic power.

ALL THE BEERS!

Caramel malts Light to dark amber malt. Color comes from caramelized sugar. Little diastatic power. Also called crystal malts.

many types of beer

Dark malt Heavily kilned malt. Nearly no diastatic power. stouts, bocks

Light malts Slightly darker than base malts. pale ales and lagers

Chocolate malt Dark brown porters, stouts

Black malt Practically scorched malt. Adds a good deal of non-hop bitterness.

stouts

designed to separate the sugar solution (called wort) from the mash, and to add some more flavors to the beer – in – progress. Like malting, brewing also has 3 parts to it: mashing, lautering, and kettle boil.

1) Mashing – Mashing involves adding the kilned malt to water. At this point, the malt in water is referred to as mash. The mash is heated up to 60°C in order to activate the amylase present in the wort. Mashing is also the point where adjuncts and flavors (i.e. chocolate and coffee) are added, with the exception of hops.

2) Lautering – Lautering simply involves the separation of the liquid from the solid part of the mash. To do this, special vessels called lauter tuns are used. The lauter tun filters the mash, then sprays (called sparging) the mash with boiling water in order to wash any remaining wort from the mash. In the lauter tun, a coarse grist helps to filter out the wort. On the other hand, using finely – milled mash to make malt could result in problems in the lauter tun.

3) Kettle boil – Boiling the wort prior to fermentation is done for several reasons, first boiling helps kill many nuisance microorganisms (like wild yeast and lactic acid producing bacteria) in the wort. Boiling also destroys many proteins. Destroying certain proteins will prevent the development of off – flavors. Finally, but most important in terms of flavor, hops are added to the boiling wort. The boiling water helps to free the alpha acids and essential oils from the hops’ lupulin glands. In practice, hops are added to the kettle at certain times, and this is often referred to as a “hop schedule”.

Wet and Dry Hopping

In recent years, it has become increasingly popular to “dry hop” certain beers in order to impart unique flavors. Dry hopping refers to adding hops during or after fermentation (usually in addition to the hops that are added in the kettle. If you dry hop at home, you usually have a fermentation that looks like this:

As a not – quite contrast, “wet hopping” means to add fresh hops that aren’t dried out. In case you’re wondering, it’s completely possible to dry hop with wet hops!

Fermenting Even if “major errors” are committed in the malting and brewing processes, as long as fermentation occurs, you can still call your product beer! That makes the fermentation step the most important step in beer production. Prior to fermentation, the wort must be cooled down to temperatures that are not harmful to the yeast you are using. This temperature is dependent on the type of yeast used. Lager yeast grows best at temperatures cooler than 10°C, while ale yeast can grow best at temperatures of up to 25°C. In large breweries, the wort is piped from the kettle to the fermenters, and the wort often passes through a heat exchanger, which helps to rapidly cool the wort to an acceptable temperature. When the wort has cooled, the wort is “pitched” (yeast added) with the appropriate yeast. For the 1st hour or 2 of the fermentation, the yeast is allowed to grow under aerobic conditions. Allowing the yeast to grow in oxygen allows the yeast to reproduce rapidly. More yeast (especially yeast attenuated to the wort) means more fermentation. After the yeast are allowed to grow aerobically, the yeast use up the remaining oxygen and begin to grow in an anaerobic environment. At this point, the yeast are actively fermenting the sugars in the wort to alcohol. The length of the anaerobic part of the fermentation varies by yeast type. Ale yeast require about 5 days, while lager yeast require 2 weeks. Several types of fermenters are shown below:

Bittering and Flavor

A typical kettle boil will take 60 minutes, and this is a fairly consistent practice. With so little room for misinterpretation,

you might think it’s actually easy. However, it’s not as easy as throwing all your hops into the kettle at the start of the

boil! Hops serve 3 different roles: bittering, flavoring, and aroma. A typical hop schedule for a Stone Ruination (an IPA)

clone looks like this:

Hop Amount % alpha acids Time in kettle boil

Magnum 1.75 oz 14.00 % 60 minutes

Centennial 1.00 oz 9.60 % 30 minutes

Centennial 1.00 oz 9.60 % 10 minutes

Centennial 1.00 oz 9.60 % 1 minute

Centennial 2.00 oz 9.60 % Dry Hop

In this schedule, the Magnum hops are used as bittering hops, and you can tell this because they are added at the start of

a boil. It takes a longer amount of time to extract bitter flavors from hops than to extract other flavors. Centennial is used

for flavoring and aroma. Excessive heating will remove a lot of the flavor compounds from beer, so flavoring and aroma

hops are added later into the boil.

From left to right: homebrewing carboy, craft brewer fermenters, fermentation towers

Maturing Maturing beer after fermentation serves several purposes. Maturing time allows beer flavor to fully develop and stabilize. Typically, ales mature from 6 – 8 days while lagers require 2 -3 weeks to mature. Although both ales and lagers mature at cooler than fermentation temperatures, lagers are matured at much colder temperatures (close to freezing). Occasionally, some types of ales are allowed to mature in barrels that were previously used in aging whiskey. Aging ale in barrels once used for aging whiskey will cause the ale to pick up whiskey – like flavors from the barrel. In the US, bourbon barrels are most prized when aging beer this way. Maturing beer also allows for the development of carbonation. Conditioning (adding carbonation by aging) a beer is done several ways.

– Bottle conditioning – adding live yeast to bottled beer to start a secondary fermentation or adding sugar to unfiltered beer, typical to Belgian beers

– Cask conditioning – beer is conditioned and dispensed from a cask, typical in many English styles Most often though, carbon dioxide (usually collected from the fermenter) is injected into beer. While this isn’t conditioning per se, the end result is often the same as in conditioning. Carbonation through injection almost always results in short – lived heads, while conditioning yields larger, more stable heads. In conditioning, the yeast can be left in the beer or removed through the use of fining agents (fish bladders, gelatin, plastic dust). Packaging Here’s a couple of points about packaging: