"Session Beer" is a relatively recent term that is entirely made-up, but refers to beer that is of a lower alcohol content (typically under 5%) that allow for drinking more than one in a single "session". The challenge with brewing beers of lower alcohol strength is in ensuring that they have enough flavor to keep them interesting, and enough balance to invite multiple rounds. In this blog post I'll cover some takeaways from Jennifer Talley's new book Session Beers, including relevant styles and brewing tips. Talley has spent majority of her brewing career in Salt Lake City, Utah where she was restrained to brewing low-alcohol beers due to state laws. Out of necessity she has learned to brew great beer under 5% ABV and shares her tips (and recipes) in this 2017 publication.

The best way to read about session beer is to read while enjoying a session beer.

Historical Session Beer

To start, let's have a look at some of the classic styles that fall under the category of "session beer". Descriptions of these styles are borrowed from the 2015 BJCP Style Guide.

England

English Bitter

Both Ordinary Bitter and Best Bitter were derived from the pale ales of England in the late 1800s. These beers are conditioned through secondary fermentation in the cask and served at cellar temperatures and with a naturally low carbonation level. Bitters are typically made with pale, amber, and/or crystal malts, resulting in a wide range of colors from golden to ocher brown. Despite the name, Bitters are not overly hopped, with IBUs ranging from 20-40.

OG: 1.030 - 1.048 ABV: 3-5% IBU: 20-35 (Ordinary) & 28-40 (Best)

Mild Ale

Mild or Dark Mild ale was historically a fresh beer used to mix with stale beer in the market. They are darker in color and have a malty, sweet taste from the dextrinous pale British base malt and the use of crystal and dark crystal malts. This was a worker's drink due to its maltier profile and cheaper price.

OG: 1.030 - 1.038 ABV: 3.0 - 3.8% IBU: 10-25

Ireland

Dry Stout

London porter was the precursor to the Dry Stout which emerged with the invention of black patent malt in 1817 by Daniel Wheeler. Today they are made using either unmalted roasted barley or chocolate/other roasted malts. The color must be practically black with a strong, roasted, almost coffee-like flavor. Draught versions are dispensed using nitrogen (in the case of Guinness) for an extra smooth, creamy mouthfeel.

OG: 1.036 - 1.044 ABV: 4.0 - 4.5% IBU: 25 - 45

Red Ale

Smithwick's in Kilkenny started brewing Red Ale in 1710, although the name wasn't introduced until Coor's released the Killian's Irish Red in the early '80s. The red color actually comes from roasted barley with a caramel malt profile. The high amounts of bicarbonate in Dublin water make it necessary to use various amounts of roasted malts in order to drive the mash pH into the desirable 5.2-5.5 range. The combination of minerally flavor and caramel malt sweetness with a dry finish are characteristic for the style.

OG: 1.036 - 1.046 ABV: 3.8 - 5.0% IBU: 18 - 28

Scotland

60 Shilling

Originating from the taxation system based on alcohol strength in Britain, the 60/ ("60 shilling") referred to the cost per barrel and ran all the way up to 160/ for strong ale (9% ABV). The low ABV (3.5%) 60 Shilling would have been the last run using the "Parti-Gyle" system in which the same grain was mashed and sparged/lautered multiple times in order to brew three different strength beers. The problem here is that the lowest strength wort would also have the most alkaline water which would increase phenol extraction which would likely have resulted in harsh, astringent finishes for these beers (low quality session beer historically). In terms of flavor, these are malt-forward beers with a range of malt flavor, excluding roasted. They tend to be darker in color and derive their flavor from specialty malt, as opposed to extended boil times/caramelization in the kettle.

OG: 1.030 - 1.035 ABV: 2.5 - 3.2% IBU: 10 - 20

Belgium

Saison

While modern-day examples of saison tend to be much stronger, the original "farmhouse ales" of Wallonia and northeastern France were very light and refreshing beers. The low alcohol content was necessary at the time due to the volume consumed by farm labourers. Recipes varied from farm to farm, but the malt bill would be primarily pilsner malt with alternative grains such as wheat, spelt, buckwheat, rye and oats. The dry finish is another characteristic of this style that comes from very low final gravity due mainly from the yeast which has evolved from a mixed fermentation that likely included bacteria at some point. The optional addition of spices make this style truly a beer for all seasons.

OG: 1.048 - 1.065 ABV: 3.5 - 5.0% IBU: 20 - 35

Witbier

"White Beers" are wheat beers that are unfiltered, cloudy, and with a frothy white head. A blend of malted and unmalted wheat yield the cloudy appearance. Hops are subtle in this style and instead, the addition of orange peel, coriander, grains of paradise and other spices add layers of complexity. Some lactic sourness is acceptable which can make this beer even more refreshing. Hoegaarden is probably the most popular town for this style, after being revived by Pierre Celis in the 1950s.

OG: 1.044 - 1.052 ABV: 4.5 - 5.5% IBU: 8 - 20

Germany

Berliner Weisse

The "Champagne of the North" as described by Napoleon's soldiers in the early 19th century has been brewed since 1680 is characteristically tart, dry and slightly fruity. Mixed fermentation of Lactobacillus delbrueckii and Sacharomyces cerevisae leads to a high degree of attenuation and the resulting pH of this beer is in the 3.2 - 3.4 range. In Berlin, traditionally there is the option of serving the beer along with a shot of sweet syrup (raspberry or Waldmeister).

OG: 1.028 - 1.032 ABV: 2.8 - 3.8% IBU: 3 - 8

Weissbier/Hefeweizen

Bavarian wheat beers have been enjoyed since the 17th century in southern Germany and are an excellent session beer that is available in a few varieties: hefeweizen (pale, unfiltered), dunks weissbier (dark, unfiltered), and kristallweizen (pale, filtered). The grist includes at least 50% malted wheat, but may include up to 70% with the rest being Pilsner, Munich or Vienna malt depending on the variation. All of these (and most German beer) fall under the category of "vollbier" (whole beer) based on the beer tax structure which puts these between 3.5 - 5.5% ABV. These beers don't have the sour taste like Berliner weisse, but do have characteristic phenolic and estery flavours from the yeast in the form of 4-vinylguaiacol ("clove") and isoamylacetate ("banana").

OG: 1.044 - 1.052 ABV: 4.3 - 5.6% IBU: 8 - 15

Helles

The Helles was introduced in Munich by Spaten in 1894 and quickly exceeded its predecessor, the Dunkel. It is a masterpiece in showcasing high-quality malt without the bitterness or hop nose of a Pilsener. It continues to be the most popular beer in Bavaria hands-down. A high protein level gives it a medium-to-full-body with a rich head and the dry finish leaves you coming back for more.

OG: 1.044 - 1.048 ABV: 4.7 - 5.4% IBU: 16 - 22

Munich Dunkel

Gabriel Sedlmeyer is credited with introducing this style to Europe after an inspiring trip to Britain in 1833 which opened his eyes to pale malt, as well as his co-discovery of lager yeast in 1841 from a Bavarian monastery. While attempting to brew a pale lager at his family-run Spaten brewery in Munich, the local malting technology at the time resulted in a darker version of his target and the Munich Dunkel was born. This is a very easy-to-drink, malt-forward beer that lacks roasted character.

OG: 1.048 - 1.056 ABV: 4.5 - 5.6% IBU: 18 - 28

Pilsener

The most highly-consumed beer in Germany is the straw-coloured, hop-forward pale lager with a dry finish, commonly known as the Pilsener. Spaten, Warsteiner, and Bitburger all make traditional examples of this style which is decidedly bitter in comparison with the German Helles and the Czech Pilsner.

OG: 1.044 - 1.050 ABV: 4.4 - 5.2% IBU: 22 - 40

Schwarzbier

The "black Pilsener" is one of the few beers with roasted malt character but brewed with a lager yeast. Developed in Kulmbach, northern Bavaria (Kloster Monchshof) and Bad Kostritz in Thuringia (Kostritzer) since 1543, the Schwarzbier is composed of a base of Munich or Pilsner malts along with Carafa-type roasted malts. The result is a dark lager with balance and a dry finish that makes it very sessionable

OG: 1.046 - 1.052 ABV: 4.4 - 5.4% IBU: 20 - 30

Kolsch

The city of Cologne (Koln in German) responded in the 1800s to the growing popularity of bottom-fermented pale lagers with their own TOP-fermented, clean, crisp, pale beer. The Kolsch is cold-conditioned to give the clean taste, with slightly more fruitiness in comparison to bottom-fermented beers and it's traditionally served in 0.2 L glasses (Stange).

OG: 1.044 - 1.050 ABV: 4.4 - 5.2% IBU: 18 - 30

Altbier

One of the oldest ale styles in Germany was introduced in Dusseldorf in 873. It means "old" beer but this refers to the old way of brewing with top-fermenting yeast and the extended conditioning time during secondary fermentation. Similar to the Kolsch, it's fermented with an ale yeast at lower temperatures and lagered for an longer period than typical ales. It's described as well-balanced, well-attenuated, bitter yet malty, clean and smooth amber-colored beer.

OG: 1.044 - 1.052 ABV: 4.3 - 5.5% IBU: 25 - 50

Austria

Vienna Lager

Anton Dreher shared the same experiences with Gabriel Sedlmeyer (see Munich Dunkel) and independently developed this style out of the Schwechat Brewery in Vienna. Similar to Sedlmeyer, Dreher utilised darker malts that were available to develop this toasty-malty, amber-colored lager. It features noble-hop character, but not at the same level of bitterness as compared to the German Pils. This became the precursor to many Mexican amber lagers brewed in the 19th century by immigrants.

OG: 1.048 - 1.055 ABV: 4.7 - 5.5% IBU: 18 - 30

Czech Republic

Czech Pilsner

The town of Pilsen, in Bohemia, is considered to be the birthplace of the Pilsner style. Ironically it was an immigrant from Bavaria, Josef Groll, using a lager yeast brought by a Bavarian monk that produced the Bohemian Pilsner (aka Czech Pilsner). Compared with other European lagers, the Czech Pils has a more assertive hop character than the Munich Helles, but is more malt-forward compared with the German Pils. Budweiser Budvar and Pilsner Urquell are two authentic examples still being widely produced today.

OG: 1.044 - 1.060 ABV: 4.2 - 5.8% IBU: 30 - 45

New World

Adjunct Lager

Immigrants from Europe brought their trades with them in the 19th and 20th century and their love for pale lager beer. Adjusting to the availability of raw materials, many 'new world' lager recipes started to include 25 - 40% non-malt (adjunct) ingredients such as corn, rice, and sugar which reduced the body and produced a very different taste from the original recipes in Europe. Today this is by far the most popular beer style in the world - found in nearly every country. It's a highly carbonated, light-bodied, straw-color, refreshing beer that is practically the definition of a session beer.

OG: 1.028 - 1.040 ABV: 2.8 - 4.2% IBU: 8 - 12

Session IPA

Most IPAs are too high in alcohol to be considered "sessionable". This style was introduced at the Great American Beer Festival (GABF) in 2015 and are basically IPAs with lower alcohol strength. They can be described as hoppy pale beers, light to medium in body, with dry finish, fantastic hop flavor, and pungent hop aroma.

OG: 1.038 - 1.052 ABV: 3.7 - 5.0% IBU: 40 - 55

Gose

A 1,000 year-old style from the city of Goslar, Germany and popularised in Leipzig, the Gose (GO-zeh) is described as a sour and saline tasting ale fermented with both Saccharomyces yeast and Lactobacillus. Coriander may also be added along with conservative hop additions, on top of a base of 50% wheat and 50% pilsner malt. I list it here with "New World" beer since it has largely been resurrected by the craft brewing movement - specifically in North America.

OG: 1.036 - 1.056 ABV: 4.2 - 4.8% IBU: 5 - 12

Cream Ale

No dairy products in this one, despite the name. The cream ale is dubbed the "lawnmower beer" and is a clean, well-attenuated, flavourful, easy-drinking, and refreshing straw-coloured beer with more character than a typical American lager. Malt is typically 6-row or a combination of 6-row and 2-row, along with adjuncts such as corn or sugar (up to 20%). Lightly hopped with any American variety.

OG: 1.042 - 1.055 ABV: 4.2 - 5.6% IBU: 8 - 20

Brewing Session Beer

One consistent theme throughout the book is that brewing session beer is all about achieving balance. Without the strength of alcohol, other flavours become amplified in the beer which means you must be extra careful to avoid defects, but also sensible in using other ingredients so that nothing is too overpowering. It's helpful to picture the final beer before starting to build your recipe, so consider using one of the classic styles above and then follow the rest of the tips that follow.

Ingredients

Malt

Go with a base malt that is representative of the style that you're brewing (i.e. UK, Germany, USA).
When desiring a darker color, a combination of a small amount of a mid-range caramel malt with a larger amount of a low-color caramel malt is recommended to not add too much caramel flavor.
For roasted malt, go with a dehusked black malt such as Weyermann Carafe Special III. You can even use this malt for a blood-red color by adding it to the top of your grain bed and allowing the sparge water to extract that color.
Dextrin malt at 1 - 5% is recommended to add mouthfeel and body. Consider using Carapils for mouthfeel, foam stability, and improved head retention without impact on flavor or color.
Munich malt can also be used to increase body and mouthfeel (5 - 10% of grain bill), or in larger quantities as a base malt for darker styles.

Water

If using mostly pale malts, mash water must be acidified to reach mash pH of 5.2.
Avoid rising pH of the mash during sparging with high-alkaline water, which will extract polyphenols from the malt husk and give you a harsh-tasting beer
Adding calcium to the mash protects against rising pH and helps enhance starch conversion. You can add it in the form of calcium chloride, calcium sulphate or calcium carbonate. Calcium chloride tends to provide a palate fullness while calcium sulphate aids in enhancing a dry finish. Calcium carbonate is commonly used as a pH buffer when using higher amounts of roasted malts.

Mashing

Shoot for a rest temperature of around 68 - 69 C to favor the alpha amylase enzyme and, therefore, leave more unfermentable dextrins so that there is enough body in the beer

Boiling/Hop Additions

Check the pre-boil gravity (when the kettle is full) to determine if you need to dilute the wort with water at the beginning of the boil, rather than making additions at the end.
Be aware that only 40% of dissolved calcium in the mash carries over to the boil, in case you need to add more minerals for your yeast.
Lower IBUs are generally necessary for session beers (12 - 47 IBUs). Quite a range to work with, but you can use the style descriptions above for a starting point. It might take some trial-and-error to determine your target IBU level.

Yeast/Fermentation

Don't go for high residual sweetness. Starting with a higher gravity beer and prematurely chilling it to drop out the yeast and leave unfermented sugar in the beer will not necessarily make a highly drinkable beer. The extra sugar can also lead to a greater risk of bacterial infection. Doing this will also likely lead to inappropriate levels of diacetyl in the beer since the yeast won't have the chance to clean it up.
Ensure a healthy pitching rate of 1 million cells per degree Plato (or around 250 mL of fresh yeast slurry for a 20-liter batch).
Control your fermentation temperature to avoid any off-flavors from the yeast (i.e. fusel alcohols).
Properly aerate the wort to 8-10 ppm of dissolved oxygen before pitching to ensure a healthy fermentation.

Maturation/Conditioning

Perform a diacetyl rest 24 hours after fermentation is complete. "Complete fermentation" occurs when there is no more than a 0.15 P drop over a 24-hr period. The range of attenuation of most brewing yeasts is 65 - 85%, so you'll have to use experience to know the typical behaviour of the strain with which you are working.
Consider using finings such as gelatine, isinglass or silicic acid to clarify your beer.
When adding specialty ingredients, Talley prefers adding infusions on the cold side vs. steeping on the hot-side.

Final Thoughts

When it comes to brewing Session Beers it is all about "drinkability" which can be difficult to define exactly, but it implies that there is balance in the glass and the flavors come together to encourage drinking more. Aspects of drinkability would include the absence of off-flavors such as dimethyl sulphide (DMS) or diacetyl, as well as careful attention to other sensory components such as carbonation level, hop bitterness and aroma, phenolic and ester compounds, protein levels, ratio between sugar and pH, and alcohol content.

It seems that in the brewing history of the USA (and perhaps other countries as well), demand shifted towards lighter beer with less flavor and excellent session-ability (Pabst, Miller, Budweiser, Coors, etc) in the post-WWII era before the resurgence of the craft-beer movement when it was about more flavor, bitterness, intensity, etc in the late 20th-century. Now we are seeing the pendulum swing back slightly with these craft brewers offering less-intense, lower-alcohol, yet flavourful brews that will keep us coming back for more.

In terms of home brewing, we can lean towards creating very experimental beers with a high ABV or that integrate exciting new ingredients, but oftentimes the intense flavours are only masking some of the flaws in our process and sanitation. There is certainly much that can be said of simply being able to deliver nice, clean, balanced beers to share with our friends that are either our best stab at a classic session style from earlier in this post, or a successful marriage of new combinations of malt, hops, water and yeast.