Once in a while I go through the area below the workbench in my basement brewery and check on the bottles that reside there to restore order to any chaos that has developed. Time plays a role in more than my collection of beer becoming a bit disorganized, it also provides an opportunity for the beer to change. Some of the beer is left to change for the better, and some gets moved into the queue to be consumed before changing for the worse. Even though I make a concerted effort to place the beers that need to age in order so they can remain undisturbed for an extended period of time, once in a while I lose track of a few. A case in point was a bottle of doppelbock that had been forgotten for 13 years. When I did sample it, I was delighted to find that it was like drinking a liquid brownie! I recalled what that beer tasted like when it was younger and how it improved with age until I drank what I thought was the last one at seven years of age. The seven-year-old bottle was very good, but the 13-year-old bottle was awesome! Thus, I have learned that brewing beers to age can be well worth the time and effort.
Style to Age
If you are considering brewing a beer to age; give careful consideration to what styles of beer lend themselves to being aged. Beer connoisseurs often point to the three “S’s” of the types of beers to age: Strong, sour, and smoked. This is not a hard and fast rule, but serves as a good starting place for consideration of what types of beer can benefit from the passage of time. Strong beers are those that are typically both of high starting gravity and subsequently high in alcoholic strength (greater than 8% alcohol by volume). Sour beers are those that have become acidic from the activity of microorganisms such as Lactobacillus or Pediococcus, or a combination of the two. Smoked beers are those made with a certain percentage of malt that has been exposed to wood or peat smoke after or during kilning. There are several reasons why strong, sour, and smoked beers improve with age, and also why other types of beer might decline with age.
Just as there are styles of beer that age well, there are other styles that do not. Generally speaking, beers with a great deal of hop flavor and/or aroma will simply lose their wonderful hoppiness over time. However, heavily hopped beers that use high beta acid hops, such as many European varieties, will maintain their bitterness longer and can even evolve in taste with new pleasant fruity flavors emerging. Lower-alcohol beers will also fade with age, becoming bland and simple in both flavor and aroma. A few years ago, a member of our homebrew club brought a can of commemorative light lager to our monthly meeting that he had stored away for over 20 years. The beer tasted like aluminum-flavored club soda; lesson learned. Likewise, most wheat beers do not age well due to the higher protein level typically found in wheat malt that will combine with oxygen and drop out of solution, leaving the beer thinner in body as it ages. For many styles of beer, the changes in flavor and aroma that occur with time are not favorable. For lighter and hoppier beers, fresh is best.
How Beers Evolve
Some of the changes that occur as beer ages are simply the result of chemical processes, while some are biologically orchestrated. Bottle-conditioned beers that retain the microorganisms that fermented them initially will age a bit differently than beers that are filtered before packaging. Most of the significant chemical changes that occur as beer ages have to do with oxygen. A beer that is said to be “oxidized” will typically have paper, cardboard, stale, Sherry-like, or even burnt flavors. These undesirable flavors can occur more readily in beers of lower starting gravity rather than in strong beers. More about this in a bit. However, an excessive amount of oxygen should be avoided at packaging to keep beer as free of oxygen as possible.
Residual sugar and protein are also important components of beer that change with age. Since virtually every beer has some amount of residual sugar and protein in it, what becomes important is the amount of each in the beer at packaging. Let’s look at each of the three types of beer mentioned earlier — strong, sour, and smoked — to see why and how they age the way that they do to help us understand the basics of aging any type of beer.
As mentioned previously, strong beers typically have both a high starting gravity before fermentation and are subsequently high in alcoholic strength after fermentation. Depending on the sugars available in the wort and the attenuation capability of the yeast (or other fermentation organisms) there will be a certain type and amount of sugar remaining in the beer at bottling.
Oxygen and sugars present in beer after packaging are closely linked. Generally speaking, residual sugars chemically absorb oxygen and help prevent beer from developing oxidized off-flavors over time. Sugars that are still intact at bottling might be easily fermentable (such as dextrose) or more resistant to fermentation (such as maltotriose). Homebrewers typically use dextrose (corn sugar) to prime bottled beer as it is easily consumed by yeast; producing carbon dioxide and a bit of alcohol. This is important for short-term aging to produce carbonation (aka bottle conditioning). However, successful long-term aging will benefit from sugars that are more slowly consumed by any biology in the bottle. In this way, complex sugars can be available for the long run to absorb oxygen and morph into dried fruit or berry-like flavors instead of simply producing carbon dioxide and alcohol. Larger, less digestible sugars are particularly significant if the beer contains Brettanomyces, which can break down nearly any form of sugar over time.
Another aspect of high strength beers is the formation of higher alcohols (alcohols with more than two carbon atoms) from yeast that are stressed while trying to ferment a lot of sugar and by the ever-increasing concentration of alcohol as fermentation proceeds. A particularly warm (above 70 °F/21 °C) fermentation can also result in increased production of higher alcohols. Types of alcohol with more carbon atoms than ethanol (which has two) can make beer taste boozy or hot, and produce a burning sensation near the back of the tongue or throat. These higher alcohols don’t typically break down into simpler alcohols, but in time can combine with acids to form esters that have fruity flavors and aromas (pear, rose, banana, etc.). These esters can undergo further changes to produce dried fruit, dark fruit, toffee, caramel, or amaretto flavors. As the higher “hot” alcohols change and drop out of the flavor profile, other sweeter or more subtle flavors can become more noticeable. This can add a great deal of complexity that is cherished in many strong, aged beers. In this way, big beers that might go into the bottle a bit “rough” or “hot” may emerge years later slightly fruity, more complex, and overall more “mellow.”
Flavors from roasted malt, fruity or spicy-phenolic flavors from yeast, or essences imparted from wood, are also often found in strong beers such as stouts, old ales, and Belgian beers depending on how they were brewed or fermented. Roasted malt flavors typically change to resemble chocolate as they age. Fruity esters in ales fermented with English or Belgian yeast may change in flavor and aroma from that of pear, rose, or banana, to that of dried or dark fruit such as dried cherry, prune, or fig. Phenolic compounds often present in beers fermented with Belgian yeast may change from spicy and peppery notes to that of vanilla or other “earthy” tones.
Barrel aging beer must be done carefully, monitoring the evaporation of beer through the barrel as well as the amount of flavor the beer is developing from being in contact with the oak. Because oak flavors typically do not fade very quickly after being infused into a beer, aging beer in a barrel or on oak chips should be monitored closely until the desired “woodiness” is achieved. The beer is then removed from contact with the wood and aged further to allow other flavor changes to occur around the more stable flavors derived from the oak. Aging beer on beech wood chips is typically done while the beer is in secondary fermentation. The wood itself imparts little or no flavor to the beer; the beech wood chips simply provide a greater surface area for yeast to reside during lagering.
Sour beers have their own dynamics as they age. Generally speaking, sourness fades as a beer ages (although sometimes they may taste more sour because the other flavors have diminished at an even higher rate). As the sour character declines, other flavors that are typically part of a sour beer flavor profile become detectable, thus the beer becomes more “layered” with flavors when tasted. Because bottle-conditioned sour beers may have a variety of microorganisms present, the little beasts often continue to ferment any remaining complex sugars, producing a complexity of flavors and aromas while continuing to dry out the finish. Even though sour beers might be of lower alcoholic strength, their particularly low pH makes them less susceptible to oxidation.
Sour beers can change dramatically over time, so sampling at regular intervals can be very interesting and rewarding to learn of the many flavor profiles possible from a single sour beer.
Many smoked beers are typically also strong beers, however even when they are not high in alcohol the smoke phenols play a part in helping to preserve these beers. Wood smoke flavors age to become sweeter and more like pipe or cigar tobacco and less like wood smoke.
Peat smoked malt is very unique and very prominent when used in beer. If peat smoked malt is used in a beer recipe, it should be used in very small quantities (an ounce or two in a 5-gallon/19-L batch). Excessive peat smoked malt in a recipe can produce an offensive phenolic or medicine-like flavor. Conventional brewing wisdom says that it is best to stick with malt that has been smoked over wood, rather than peat.
Now that we have some ideas about how different beer styles change with age, let’s take a look at some things to consider when brewing your own beer for long-term storage.
There are some special considerations to make when brewing any of the beers styles in the sidebar to the right since they are not as simple or straightforward as more ordinary beers we might brew as our everyday drink. When brewing your own strong, sour, or smoked beer, we should pause and give them special planning of both ingredients and process if we are going to age and enjoy them for a long time to come. Two important points to consider for brewing strong beers is to determine how you will achieve the initial high original gravity, and how the yeast will deal with the big job of fermenting all those sugars in the wort.
For strong ales, pale malt and/or some pale malt extract usually make up the majority of the malt bill. For strong lagers, Pilsner malt is often the base malt of choice but Vienna and Munich malts are often found as well. Specialty malts such as aromatic, crystal, or dark-kilned malts will add complexity to the flavor profile, but should be kept to less than 20% of the malt bill. If adjuncts such as flaked corn, brown sugar, or other sugars are included, they should make up less than 10% of the wort’s original gravity although, as always, there are exceptions to these rules such as sugars in strong Belgian styles. Mashing malt and adjunct grains to achieve the entire original gravity can be a challenge for some homebrew mash tuns, so don’t be afraid to consider some liquid or dried malt extract to make up part of the load. Mashing a bit on the high side at 154 °F (68 °C) will add to the maltiness (and complexity of sugars) of a strong beer and help limit oxidation during long-term storage. Once you have all those sugars in your wort, you will then need a strong army of yeast to ferment them.
Whichever yeast you choose to ferment your big beer, be sure to build a considerable (3- or 4-quart/L) yeast starter culture. See the “Techniques” column “Make a Yeast Starter” I wrote in the July-August 2007 issue of Brew Your Own to learn more about this important part of brewing a strong beer. Do your best to have the temperature of the yeast starter culture and chilled wort within a few degrees of each other so the yeast can make a smooth transition into the wort and get down to business. Place the fermenter in a place at the low end of the desired temperature range for the yeast in play. Once the yeast get busy fermenting a high-gravity wort, the activity of fermentation can often raise the temperature of the liquid by 10 °F (6 °C).
The variety of hops used and the length of time they are in the boil should focus on achieving the desired level of bitterness for the beer being brewed, realizing that the flavor and aroma of late addition hops will fade considerably with time. Another thing to consider is the alpha acid and beta acid content of each variety of hops used in your recipe. Hop bitterness derived from alpha acids will fade with time. However, beta acids may change in character from bitter to fruity, and can add a nice complexity to the beer as it ages.
If you choose to package your beer by bottling, add priming sugar (such as dextrose) in the proper amount to achieve the desired level of carbonation in your beer. Many strong ales are typically not highly carbonated (usually 2 volumes of carbon dioxide or less), so about four ounces (113 grams) of priming sugar may be more appropriate than the standard 5 ounce (142 grams) dose. It is always better to weigh your priming sugar than to measure it out by volume. This assures that you get a more accurate level of carbonation during bottle conditioning.
Brewing a smoked beer (which are also often strong) is very similar to brewing a strong beer except for the addition of smoked malt in the grain bill. A traditional German rauchbier may use 100 percent beech wood smoked malt. Malt smoked with many varieties of wood is commercially available, or you can smoke some pale malt yourself. It is best to use a recipe from a reliable source as a starting point when brewing with smoked malt until you get a good handle on the impact it will make.
The topic of brewing a sour beer using organisms other than yeast is a bit complex to cover in this story. I recommend doing some homework before brewing a sour beer if you have never done so before. The “Overnight Acidification” article by Michael Tonsmeire in the January-February 2016 issue of BYO provides a good introduction to learning about brewing sour beers.
Once you have your age-intended beer brewed, there are some points to consider when looking for a place to store it for the long haul. The proverbial “cool dark place” is usually the best place to age beer. Isohumulones from hops are sensitive to light and will decline and change rapidly if not protected from it (particularly blue wavelengths). At a minimum, light will reduce hop bitterness in beer, and at worst, will chemically convert isohumulones to 3-methylbut-2-ene-1-thiol (3-MBT). 3-MBT is the stuff skunks are famous for. Brown glass bottles absorb blue wavelengths of light but do not totally exclude them. Brown glass or opaque ceramic bottles are best, but even beer stored in these bottles should be kept in a place protected from light.
Another consideration for successfully aging beer is temperature. Too cold and the beer will age very slowly, too warm and the beer will mature quickly, but with potentially negative side effects. The “Goldilocks” temperature of beer aging is 55 °F (13 °C). However, temperatures between 32 °F (0 °C) and 70 °F (21 °C) are acceptable for aging beer.
We also should consider the type of seal and orientation of each bottle of beer during long-term storage. Beer sealed with a metal crown cap should be stored upright and left undisturbed. This will allow the yeast to settle to the bottom of the bottle and make it easier to pour a sediment-free glass when the time comes to serve it.
The orientation of bottles of beer sealed with a cork and cage is the subject of much debate. If the relative humidity of your storage area is low (less than 55%), there is a greater potential for the cork to dry out if the bottle is stored upright with the cork not in contact with the beer inside the bottle. The resulting dried-out cork may allow oxygen to enter the bottle, producing cardboard-like or even burnt flavors to develop in the beer. If you live in an area like mine where the air is almost always drier than 55% relative humidity, corked bottles should be stored on their sides or you should seal your bottles with crown caps and store them upright.
Swing top bottles are a distant third option and should be avoided when packaging a beer you plan on cellaring for years as they allow the most oxygen ingress compared to the other two choices. While on the topic of picking the appropriate bottle, keep in mind that the larger the bottle the slower the beer inside will age.
One last point on the subject of beer storage is labeling. Be sure to label your bottles so you know what you are drinking (and how old it is) when you dust one off to sample. However you make labels for your bottles, be sure to include the style of beer and a date it was bottled. Do not rely on the color of the bottle cap and your memory to know what is in each bottle. I use a simple round sticker on the bottle cap to record the type of beer and the date it was bottled. I can then go back in my notes to find the details of a particular batch if I at least have marked each bottle with a style and date to guide me.
Brewing beers to age can add another very rewarding facet to the adventure of homebrewing. Thoughtfully selecting what to brew and exercising some additional care in production, packaging, and storage can help you create some real gems for the future. Developing a cellar of your own homebrewed beers will not only help you hone your skills as a brewer, but will also increase your appreciation and understanding of beer itself.
Beer styles to Age (sidebar)
A quick review of the Beer Judge Certification Program 2015 Style Guidelines can give us some ideas of strong, sour, and smoked beer styles we may wish to consider brewing to age. Candidates might include:
• 9A Doppelbock
• 9B Eisbock
• 9C Baltic Porter
• 17B Old Ale
• 17C Wee Heavy
• 17D English Barleywine
• 20C Imperial Stout
• 22B American Strong Ale
• 22C American Barleywine
• 23B Flanders Red Ale
• 23C Oud Bruin
• 23D Lambic
• 23E Gueuze
• 24C Biere de Garde
• 25C Belgian Golden Strong Ale
• 26C Belgian Trippel
• 26D Belgian Dark Strong Ale
• 28A Brett Beer
• 28B Mixed-Fermentation Sour Beer
• 32 Smoked Beer
• 33 Wood Aged Beer.