As Purim preparations swing into full gear, a trip to the local liquor store is on many people's lists. One of the common beverages purchased will likely be the iconic beer. While the general public assumes that all (or most) beers are kosher, some are highly problematic. Others may be aware that some beers have kashrus concerns, but they do not know what those are. The purpose of this article is not to reach a decisive conclusion but only to enlighten the consumer as to the issues involved. Let us now look into the issues that may arise with beer.

Beer Production
It may be helpful to begin with a brief overview of the production process. First, malted barley (and occasionally other grains) is crushed and steeped in warm water (at a range of 140F-170F) for 60-90 minutes, causing the starch to convert into sugar. The sugary water is then drained and boiled in a kettle (at 212F) for 90 minutes, during which time hops (the flower of the hop vine that gives the characteristic bitter flavor) are added. Then a fining (clarifying) agent must be added to avoid haziness. (Isinglass, the swim bladder of the non-kosher sturgeon and other fish, was commonly used for this purpose; see Noda B'Yehudah, Mahadurah Kama, Y.D. siman 26, who deals with this issue.) The thick mush is then separated, cooled to 50F-70F, and drained into fermentation tanks. Yeast is added to the mixture, and the fermentation begins. This process may take anywhere from a few days to many weeks, after which the product is cold-conditioned (cooled down to near-freezing) for many weeks. The product is then filtered and occasionally allowed to age for some time. The beer may be artificially or naturally carbonated. It is then watered down and bottled. The bottled product is later pasteurized with heat, often in a tunnel pasteurizer.
At which point is flavoring added in a flavored beer? This depends largely on the type of flavoring. Botanicals, spices, herbs, and honey may be added during the fermentation process whereas other flavorings, such as lime, may be added later in the process. This may have halachic ramifications, as will be explained below.

Reinheitsgebot 
On the surface, beer does not seem like a complex beverage from a kashrus standpoint; after all, it generally contains only four ingredients: water, barley (or another grain), hops and yeast, following tradition from just after the Middle Ages. In the year 1516, Bavarian Duke Wilhelm IV (a.k.a. William IV) instituted a set of decrees, commonly referred to as the Bavarian Reinheitsgebot (Purity Law) of 1516. He decreed that the only ingredients used for the brewing of beer must be water, barley, and hops. This was actually one of the first consumer protection laws.
The astute reader will notice that yeast was not on the list, mainly due to the fact that Louis Pasteur only discovered the effect of yeast in 1857. This is quite interesting because practically speaking, yeast is required to begin the fermentation process. How did they ferment beer without adding yeast? Early brewers managed to add yeast without realizing it: a) they either took some leftover sediment from a previous batch (referred to as brewer's yeast), or b) they left the beer vat open to the air, and after being exposed to the elements long enough, some airborne yeast made its way to the open vat. To rectify these highly impractical solutions, yeast was added to the approved ingredient list some time later. In 1906, the Reinheitsgebot became the law of the land in Germany, when Bavaria, a large region in the south of the country, wanted to become part of the new German Republic and made the acceptance of the law contingent upon its joining.
The practice of Reinheitsgebot continued until 1987 when foreign competitors complained to the European Court of Justice (EC) that the German law was a restraint to fair trade. In March 1987, the EC officially struck down the law; thereby allowing “impure” beer to be imported into Germany. However, many breweries, both in Germany and abroad, wishing to impart the "natural" image, claim to adhere to the original laws.
Based on the above, it would appear that beer is inherently kosher, because the four ingredients generally used are non-problematic. (It should be noted that beer is occasionally colored with caramel coloring; however, this does not present a kashrus concern.)

Recent Trends
Although the four basic ingredients have stayed the same, in recent years chanhes have been made. Many breweries, wishing to carve themselves a niche in the crowded beer market, began to produce flavored beers, with some flavors bordering on the incredible. Take, for example, the famous Flying Fish Exit Series, dedicated to the New Jersey Turnpike, with Exit 1 - Bayshore Oyster Stout, focusing on the New Jersey oyster. Other interesting examples are Mamma Mia! Pizza Beer and Singlecut Matzoh Beer. (Even more recently, some breweries have begun to age beer in used barrels, possibly old wine barrels, presenting an issue of stam yeinam. This is reminiscent of a problem commonly found with Scotch.) How does this impact the kosher consumer?
As with most food products, we must consider two issues: the ingredients, and the keilim (the processing equipment).

Ingredients
Any beer claiming to strictly subscribe to the Bavarian Purity Law does not present kashrus concerns with regard to ingredients (see below vis-a-vis keilim). Issues begin with those companies who do not make such a claim, or worse, advertise that they use flavorings. Flavorings are indeed kosher-sensitive, ranging from the ubiquitous oyster (cited above), to the seemingly innocent blackberry flavor. Other beers contain casein, a dairy ingredient. These ingredients may be non-kosher outright, so consumers should certainly avoid flavored beer without a reliable hechsher. In the vast majority of cases, flavorings are listed on the label, especially those that contain allergens, such as oyster or casein. So what could be the problem with unflavored beer?

Keilim (Equipment)
The main concern with beer may actually be the processing equipment. Many companies use the same equipment to produce numerous products. If a company produces unflavored beer on the same equipment as non-kosher beer, the equipment may cause all beer produced to be non-kosher. This concern exists with many different points of the production process.
As explained above, beer is produced in both hot and cold stages. During production, the product is heated with warm water, boiled in a kettle, and after bottling, it is pasteurized with heat. In addition, beer rests in the fermenter for many days. Although it is cold at that point, and cold non-kosher food generally does not affect equipment, it may affect the equipment after resting there for 24 hours (referred to as kavush). All these stages may affect the kashrus of the equipment.
How strong is this concern? A company which only produces unflavored beer is obviously free of such concerns. The concern exists only with companies who produce both flavored and unflavored beer. We will discuss four reasons why this may, or may not, be an issue.

1) Bitul (Nullification)
The first question we must address is the nature of the flavorings. Firstly, in the majority of cases, flavorings are potentially kosher. This may include botanicals, toasted wheat and rye, and herbs. Although one should not drink such beer without reliable certification, they will likely not affect the processing equipment. When actual non-kosher flavorings are used, these flavorings are generally present in small quantities. Furthermore, when companies use crab flavoring, for example, often only a small amount of actual crab is used - the rest of the flavoring comes from a small volume of crab flavoring.
Accordingly, some argue, even if the actual product containing the non-kosher ingredient may be prohibited, perhaps the volume of the kosher beer used in the same equipment is great enough to nullify the non-kosher ingredient. If the volume of the kosher beer is at least sixty times greater than the non-kosher ingredient used in the non-kosher beer (bitul b'shishim), kosher beer made on the same equipment may remain acceptable.
This, however, naturally depends on the size of the equipment in use. In large companies, the equipment may be large enough (and with thin enough walls) to contain the necessary ratio. In small companies, however, this may not be the case.
Additionally, this leniency is somewhat limited based on considerations of avidah l'ta'ama and chanan; these topics are beyond the scope of this article.

2) Ben-yomo
Equipment used for non-kosher products can only affect other products if produced within 24 hours of the non-kosher item. If 24 hours have passed (a situation referred to as aino ben-yomo), the product will not be affected. In large factories, where production often continues non-stop, a period of 24 hours of downtime may not be common. In small factories, however, it is possible that the keilim are not ben-yomo because they likely do not run seven days a week. Accordingly, it may be possible to be lenient on unflavored beer, working on the assumption that 24 hours have passed from non-kosher production. Relying on this as a matter of policy is debatable.

3) Cleaning
When dealing with certain products, companies often have segregated production runs. This is especially true when producing foods with allergens, such as oyster. In order to segregate highly allergic foods, companies may dedicate production lines to such products, or more often, they do a thorough cleaning after such a run. Additionally, companies often do a complete cleaning between products when running products with different taste and flavor profiles. These cleanings, when done with high temperatures, may possibly be considered a kashering of the equipment.
On the other hand, it is important to consider the fact that kashering should only be done when equipment is not ben-yomo (used within 24 hours). As previously explained, it is quite likely- especially in large factories - that the manufacturing equipment is ben-yomo. Accordingly, assuming that a factory's cleaning process counts as a kashering is highly questionable.

4) Hot or Cold
Another factor to consider is the point in the process at which non-kosher ingredients are introduced. Generally, flavorings can affect the production equipment only when the product is hot; flavorings added when the product is cold will likely not affect the kosher status of the equipment (unless it rests there for 24 hours, as explained above). The fermentation process involves high levels of heat, as explained above. Logically, certain flavorings should be added after the fermentation, before bottling. The reason for this is quite simple - crab, oyster, and the like do not ferment! If flavorings are added after fermentation, the keilim may not be prohibited, because the product is at room temperature. Although the bottled product is later pasteurized with heat, this is unlikely to affect the kashrus status of the pasteurizer for various reasons.
Small breweries, also known as "craft" or "artisan" breweries, experiment with all sorts of flavorings. Wishing to be unique, they may even add distinctive ingredients before the fermenting stage. Although this seems to be counter-intuitive, because oyster and lobster do not ferment, this creates the exact distinctiveness they crave. The unsuspecting consumer does not realize the absurdity of the additions, thinking only that this is something special, something worth trying.
From a practical kashrus standpoint, if the flavorings were indeed added before fermenting, and were present during the hot stages of production, the equipment could truly become non-kosher. In addition, after resting 24 hours in the fermenter, the fermenter would also become non-kosher.

To summarize:

• Unflavored beer produced in factories which only produce unflavored beer, does not require hashgacha. This applies to both light and dark beer, both full calorie and light versions.
• Flavored beer certainly requires reliable kosher certification. (Herbal flavors may in fact be kosher, but each product requires individual research.)
• Unflavored beer produced in a factory which also makes flavored beer appears to have some serious kashrus issues. Unflavored beer from large companies appears to be less problematic due to the fact that they generally do not experiment with such unusual flavorings. (The notable exception is Budweiser Chelada, a mixture of beer and clam juice; see Sappirim, a cRc publication by Rabbi Dovid Cohen, Issue 15, November 2008, for more details.) Checking the label for dairy or other allergen statements may be a prudent measure.
• The main concerns appear to be in microbreweries due to their non-kosher flavorings. As explained, this applies to both the flavored and the non-flavored products. It is sometimes difficult to verify what is classified as a microbrewery as opposed to a large company, but the general protocol is to ascertain the product's market: a beer which is only available in a local region is likely a microbrewery.

Is it time to require hashgacha for beer?
The modern-day kosher consumer has high standards. Relying on various questionable leniencies may not be the proper thing to do. The consumer wishing to avoid all possible questions may well be better off purchasing beer with a reliable hechsher, and there are numerous beers currently available with hashgacha. In fact, the cRc Liquor List currently has over 250 recommended beers. Therefore, before purchasing a non-certified beer, one may want to stop and consider the issues involved.

Let us do our utmost to ensure that this Purim - and all year round - we will stay true to the kosher standard we all strive to achieve.