Aged like a fine... Beer?

Yes, we are talking about aging and cellaring beer. What? You’ve never heard of aging beer?! Yes, it’s a thing. And it’s a wonderful thing! By the way: for the purpose of this article, “aging” and “cellaring” are used interchangeably. Beer cellaring is far from cut & dry. Follow me down the cellar. Watch your step...

(Photo source below)

What Beers to Age and How:

Possibly the most common question regarding beer aging is: what beers should I age? In his book Tasting Beer, Randy Mosher says, “Ales are, primarily, with bottle-conditioned ones preferred, as the yeast provides a bit of a protective effect.” Although it does not have any preservative properties, yeast does add character over time and helps provide longevity in the form of unique flavor development. Take care to not store bottle-conditioned beers in excess heat. This will cause the yeast autolysis (the death of yeast: rupturing the cell-walls releasing an array of compounds into the beer) and completely ruining your efforts. More on this down below. Speaking of temperature...

Recommended cellar temperatures are about 50° – 60°F. Some publication say 55° – 65°F. Basically this is the range a typical cellar. So when you hear someone say “cellar temperature” this is roughly the range they are talking about. Extreme temperature fluctuations should be avoided. Humidity might be a factor when regarding corked bottles. However, there is humidity inside the bottle, so this shouldn't be a problem as long the environment isn't extremely dry. A bit more on corks in the following section.

I once had a 3-year-old Corona which was kept unrefrigerated in an uninsulated garage where temperatures exceeded 110°F during the summer. Yes, I tasted this on purpose. Why? For science! There was also a fresh (well, recently purchased) bottle of Corona there for comparison.

I took the first sample. It was awful! Next, I proceeded to sample the 3-year-old Corona... (*taps microphone* Is this thing on? Ha!) Seriously though, the flavors of the aged Corona were astonishing. Think rancid apple juice mixed with vinegar and skunk spray. Yummy, right?

Besides the ridiculous heat, a Corona isn’t exactly a poster-child for the suggested beers to age. Typically, most will say to keep the ABV at 7% or higher and I tend to agree with this statement. Ethanol (the alcohol found in beer) is great for stability. Usually, darker colored beers tend to age better, too. As beer ages there’s bound to be some oxidation. In lighter beers this oxidation will cause paper/cardboard flavors in your beer. On the flip side, when aging darker colored beers, this same oxidation happens, but the highly kilned malts used will to evolve into a nutty, port and/or sherry-like characters and possibly some anise notes to add unique complexity.

Hops aroma and flavor will degrade and drop out followed by bitterness. Highly-hopped beers are usually not suitable for aging because of this.

Beers stored upright in a temperature-controlled fridge

Bottle Orientation:

Now for the bottle orientation. This is where the most vocal opinions reside on this subject. Most will say always keep your bottles upright while some say to lay them horizontal on a rack. Here’s the debate: Corks kept in a dry environment have to potential to dry out and shrink. Notice I’ve said "potential." There are many factors that I won’t get into here, but it CAN happen. That DOES NOT mean it ALWAYS happens. A solution would be to lay the beer on its side to keep the cork wet. However, this may cause a compound known as 2,4,6-Trichloroanisole (TCA) to add its musty flavors into the beer since the fungus thought to cause TCA thrives in corks.

With that said, sour and wild beers in corked bottles are what I believe to be the driving factor in this debate. Souring organisms are usually still present in a wild ale. Under aerobic conditions (presence of oxygen), the souring organism Acetobacter will begin to produce Acetic Acid essentially turning the beer into vinegar. Therefore, if the sour ale is bottles with a cork, there is argument towards laying these beers down to keep the cork wet keeping oxygen out. The downside: beer contacting the cork increasing the chances of TCA imparting its musty cellar traits.

My suggestion? Keep non-sour or non-wild beers upright, and lay down corked sours/wilds. If you do lay down your beers, turn them upright for a day or so to allow any sediment to drop and collect at the bottom of the bottle.

Vertical tasting of 2006 through 2015 Stone IRS
(Photo by Chris Scott)

Off-Flavors:

Off-flavor development is quite common with aged beer, although they are not always negative, depending on concentration. Autolysis (as mentioned above) can impart a broth-like aroma to a beer when it’s in small quantities, yet it can be absolutely disgusting in high concentrations. Imagine rotten garbage water. This is caused by all the Mercaptan compounds released during autolysis.

Oxidation is caused by the formation of the compound Trans-2-nonanal. As mentioned above, this adds a sherry or port quality to beers made with dark and specialty malts. In light beers or in extremely high quantities, it tastes like wet cardboard.

Diacetyl can also form in ages beer. Click here for my previous post about Diacetyl to find out more.

Acetaldehyde adds a green apple/sour apple, or even latex paint aromas. This compound is produced during normal yeast metabolism and is reduced into ethanol. Over oxidation can convert ethanol back to acetaldehyde.

Acetic Acid is caused by the bacteria Acetobacter under the presence of oxygen. See section above.

Big hoppy beers are best enjoyed fresh. As highly-hopped beers age, those intense hop aromas and flavors drop out and make way for the compound Beta-Damascenone. This creates a berry-like aroma and flavor that may or may it be pleasant.

There’s a slew of other compounds which degrade, arise, and may degrade again making way for even more complex compounds during beer aging. The chemistry is complex and it is tough to know the end result will be desirable or not.

Notable Exceptions:

Lambics are complex! The blended Lambics, Gueuze, are low in ABV (usually under 6%) and quite light in color. Yet, they can age for many years! This already complex style gets weirder under the right cellar conditions. These artisan and ancient beers are the only remaining beers to be spontaneously fermented by the natural airborne microflora (bacteria and fungi from a particular habitat) found in the outskirts of Brussels, Belgium. Garrett Oliver says in The Oxford Companion to Beer, “Because of the interactions between its complex microflora, the aging of lambic is unique among beers… In lambic, the microflora represent the biggest influence over the period of aging, but other factors are at work as well.”

Vintage bottles of Gueuze
(Photo by Ralph Turner)

Double and "triple" IPAs are very popular. As stated above, these intensely floral, aromatic, bitter beers are best fresh. However, there are some who believe an aged Double IPA or Imperial Red morphs into Barleywine-ish beer over time. It's an interesting thought and worth experimenting. It will not always work, but it can. Dogfish Head's 120 Minute IPA can age gracefully. It's not the same beer when aged, of course. The abundance of malts used and the elevated ABV makes for a splendid beer when cellared properly. I’ve had more disasters than successes when aging hoppy beers. Proceed with caution should you choose to age a big Double IPA.

Pigmentation:

When an aged wine is finally uncorked, white wine develops color leaning towards a golden shade, and red wine fades down to a strange redish-brownish color. Beer does the same thing, only with different color shifts. Aged lighter colored beers will gain shades of copper, while dark and black beers lighten up a bit. In my experience, the lightening up of dark beers is not as noticeable as the darkening of paler beers.

And there you have it!

In the end, it is entirely up to you if that bottle you have in your fridge should be opened now or later. By now it should be safe to say not all beers are meant to be aged. Don’t be afraid to experiment and ask questions. Many times, the beer label itself will have suggested aging timeframes and recommended caller temperatures. Start with that and then move on to experimentation.

I’ll leave you with this. A good friend of Terms of Enbeerment and much respected beer guide, Ed Heethuis, shared some words of wisdom on beer aging. This sums it up perfectly. “Aging beer is like making croutons. Since beer is basically liquid bread, and croutons are made from old bread...one has to choose wisely. Just like not all old bread produces great croutons, not all beer ages well.”

Let’s make some croutons! Choose your bread wisely.



Cheers!

Gilbert “Charlie” Perez, Certified Cicerone®



*Resources and Helpful Links:

http://focusonthebeer.com/2013/01/cellarmanship-part-2-how-to-store-your-hoarded-beer-properly.html/

http://www.beeradvocate.com/beer/101/store/

http://www.craftbeer.com/craft-beer-muses/cellaring-craft-beer-to-age-or-not-to-age

http://www.dogfish.com/community/blogfish/members/justin-williams/5-things-you-should-know-about-aging-beer.htm

http://draftmag.com/cellaring-technique/

http://draftmag.com/cellaring-evolving-flavors/

http://draftmag.com/the-great-cellaring-myths/

Tasting Beer by Randy Mosher

The Oxford Companion to Beer

Cellar Photo credit: pixabay.com

The "D" Word: Diacetyl

Remember when we were young and we were taught never to say bad words? I apologize in advance for all the obscene language I'm about to say.

In the beer world, there's no greater profanity than saying the "D" word. And even worse is putting that "D" in your mouth. (Get your mind out of the gutter! ...That's not what I meant!)

I am referring to Diacetyl.

Pronunciation aside (die-ASS-a-teel, DIE-a-see-till, or die-assa-TEEL), this compound causes a movie popcorn, almost rancid butter-like flavor and aroma in beer. Although Diacetyl is produced by all yeast strains during normal metabolism, its quantities are greatly affected by many factors. The main factor is the amino acid Valine and how much of it is present in the wort. Regardless of this, Diacetyl is always produced at some rate during the first few days of fermentation.

*Warning! Chemistry up-ahead!*

2, 3-Butanedione (AKA: Diacetyl)

During the initial stages of fermentation, the yeast cell creates Valine as part of its metabolism cycle. Along this pathway to create the amino acid, the compound α(Alpha)-Acetolactate is also produced. A non-enzymatic oxidative decarboxylation of α-Acetolactate (I know, right?) occurs outside the yeast cell and is converted to 2,3-Butanedione, the compound we know as "Diacetyl."

The presence of Valine is directly related to the amount of Diacetyl produced because the enzyme that produces α-Acetolactate is deactivated when the wort contains high quantities of Valine. We know Valine is an amino acid and amino acids are the building-blocks of proteins. In turn, we can assume the high concentration of proteins in wort should significantly reduce the amount of Diacetyl produced. High protein levels could cause some other problems in the finished beer, so large protein quantities is not a viable solution to control Diacetyl.

Another compound called 2,3-Pentanedione is created via an separate pathway. This compound is also sent outside the yeast cell and will end up in the finished beer if not properly reduced. 2,3-Pentanedione is believed to have similar buttery flavor and aroma properties (sometimes described as honey-like), however this compound is not produced in very high quantities as 2,3-Butanedione is.

For you chemist out there, these two compounds are Vicinal Diketones. "In chemistry-speak, 'vicinal' essentially means 'adjacent', and 'diketone' means that there are two ketone functional groups (a ketone is an oxygen double-bonded to a carbon in the middle of a carbon chain)." (Beer Sensory Science)

As fermentation wraps up, most of the previously produced 2,3-Butanedione and 2,3-Pentanedione is reabsorbed by the yeast into its cell. Through more enzymatic activity, they are converted into 2,3-Butanediol and 2,3-Pentanediol, which have a much higher threshold for us humans. In other words, Diacetyl is turned into something we can't taste.

For you brewers out there, this is typically referred to as a "Diacetyl Rest." Brewers usually aid the reabsorption of these compounds by raising the temperature during the last day or two of fermentation. This rise in temperature excites the yeast and can more easily and vigorously convert Diacetyl into the non-flavored compound.

If Diacetyl is detected in your beer, it is usually an indicator of rushed production or improper fermentation practices.

Another common contributor to Diacetyl is a bacterial infection. The most likely culprits are the little bugs called Pediococcus and/or Lactobacillus. Both of these lovely bacteria create lactic acid and can produce Diacetyl as part of their fermentation products. While they may be a welcome addition to some wild ales and artisanal sour beers, it is quite unpleasant when found in dirty draft lines that haven't been maintained or cleaned sufficiently. Infections can also occur in many stages of the fermentation process, but dirty draft lines seem to be the biggest contributor for Diacetyl via bugs.

One more discovery is Diacetyl production during beer aging. Although the levels of Diacetyl in aged beer may be undetectable because of low levels or hidden behind the veil of oxidation compounds, Diacetyl could be nonetheless present.

In very small quantities, Diacetyl can be a contributing factor to the overall flavor and aroma profile of certain styles. Most English and Irish beers tend to have some detectable levels of Diacetyl adding a pleasant buttery undertone. An interesting fact is Diacetyl is one of the differentiating characteristics between a German Pilsner and a Czech Pilsner (Czech Pilsners are expected/accepted to have low levels of Diacetyl). However, in high quantities this compound can impart a butterscotch, movie popcorn, or a rancid butter flavor and aroma.

Another interesting fact to point out is while a great number of beer drinkers might be able to detect Diacetyl with ease, there are an equal amount of us that are completely blind to it. On that same note, some are very sensitive to Diacetyl while others will only find it detectable in extremely high quantities. Should you fall under any of these parameters, it is perfectly normal since it is simply genetics.

I think that's enough foul language for one lesson. I need to go wash my mouth out with some beer... Er, soap. And put a coin in the tip jar... Er, swear jar.



Class dismissed,

-Gilbert "Charlie" Perez, Certified Cicerone®




Photo Credits:
A big thank you to BeerAndBaking's Jessica Rice McNew for her amazing photography in this article!!

Resources:
-Beer Sensory Science
-Janux Chemistry of Beer Course Materials
-White Labs
-Oxford Companion to Beer

*Beer Education - Ale vs. Lager*

Ale and lager. Which of the two is better? Before we can even begin to think about how to answer this question, we must first have a clear understanding on the differences between ales and lagers. The answer is not as clear-cut and dry as one would think.

Perhaps the question we should ask is: What is an ale and what is a lager?

The short answer is... nothing! Well, that is if we consider only the end product, which is still beer. But if we dissect this, there are only a few differences. The main few are yeast species, fermentation temperature, aging temperature & duration, and fruit character.

Yeast

This is the only real physical difference between ales and lagers. There are two types of yeast that brewers choose from. Ale yeast (also known as "top-fermenting" yeast) is called Saccharomyces Cerevisiae. This species of yeast has many different strains. Lager yeast (also known as "bottom-fermenting" yeast) is called Saccharomyces Pastorianus. As with ale yeast, this species also has many different strains. They both act the same in terms of basic fermentation metabolism and end product. Reasoning for distinguishing them as bottom or top-fermenting seems to correlate with the amount of kräusen found at the top of the fermenter.

FYI: Kräusen is the fluffy stuff that develops at the top of the fermenter that is made up of yeast and proteins and other materials frothed up as a result of yeast metabolism.

Fermentation Temperature

In general, ale yeast is usually slated to ferment at higher temperatures (65°F to 70°F, on average with some strains reaching even higher) and thus results and a vigorous, relatively quick fermentation and development of a large cap of kräusen. Lager yeast typically ferment at cooler temperatures (48°F to 58°F, on average). Because of this cooler temperature, fermentation is less violent, takes much longer, and there is less kräusen.

Aging Temperature & Duration

Ales are generally not aged for very long and are usually cold crashed (significant drop in temperature to about +/-40°F) after fermentation to allow the yeast and proteins to drop out. Dry-hopping (adding hops into the fermenter after fermentation is complete) is done at this time. Typically, an average ale is ready in as little as two to four weeks.

Lagers ferment at cooler temperatures and therefore take longer to complete. Fermentation can last a few weeks and up to a couple months in some cases. Once fermentation has finished, lagering can start. The word "lager" is the verb "to store" or put away in German. Combined with cool fermentation, lagering at about 33°F helps to further clarify the beer and allows the flavors to round out. Lagers can take many months to complete, from brew-day to packaging. Depending on the beer, lagering alone can last upwards to 6 months to a year, although 3 months is average.

Fruit Character

The aforementioned items are production-based distinctions. All of those aspects result in the one piece of evidence we can detect in both flavor and aroma: Fruit character. Ale yeast produce many fruity esters due to the quick fermentation, generally higher temperatures, and short aging. This is acceptable and desirable. Lagers on the other hand, are clean and show no fruit character. The slow fermentation caused by low temperature and long lagering times result in a malt and hops focused beer.

There will be more explanation further below, but the same can be true with beers fermented cold with ale yeast strains, which will produce very little esters. Interestingly enough, lager strains used to ferment beers at ale temperatures will indeed produce more fruit esters than they would usually do if fermented cold.

Bonus: Myths About Ales and Lagers

"Lagers have lower alcohol than ales." ...FALSE!

Being an ale does not necessarily indicate a higher ABV. True, the high-alcohol beers are usually an ale of some kind, there are also lagers available that can reach ABV's above 10%. Eisbock is one example.

"Ales are dark." ...FALSE!

Cream Ales and American Blonde Ales are quite pale in color.

"Lagers are always light in color." ...FALSE!

Doppelbock, Dunkle, American Dark Lager, and Baltic Porter are examples of lager beers that are dark brown to almost black in color.

"Lagers have more carbonation." ...FALSE!

Have you ever popped opened a bottle of Duvel? That's a Belgian Golden Strong Ale. Try to pour it without a producing a foam head at least 3 fingers high. Just try it.

Curveballs

This is probably the most important part of this article. We have hybrid beers out there to throw us a off-course and shows off how far we have come in our understanding of what used to be a clear line between ale and lager. These hybrid beers are a blend of ale and lager, usually using lager yeasts fermented at the lower end of ale temperatures and/or often involve lagering for a period of time regardless of yeast strain or species. Examples of these hybrids include Cream Ale, California Common, Kölsch, and Altbier.

California Common and  Cream Ale use an adapted lager strain to ferment at the low-end of ale temperatures (too high for some lager strains) and results in clean lager characteristics. This is historically true for Cream Ale, but is currently not that common. Kölsch and Altbier are examples of an ale yeast strains fermenting at the high-end of lager temperatures (too low for some ale stains) used to produce lager characteristics. They also go through a period of cold conditioning although the duration varies by style. Those are some examples of styles which create clean, lager-like beers using non-traditional methods.

A word on lagering: It is not uncommon for a beer fermented with ale yeast to undergo a cold-conditioning phase or for a "bottom-fermented" beer to be aged at room temperature. The resulting beer may differ from the traditional expectations, but could still be enjoyable if done correctly.

Other cuveballs are beers fermented with other organisms and/or wild yeasts. These organisms and wild yeasts (such as wild Saccharomyces, Brettanomyces, Lactobacillus, Pediococcus, and Acetobacter) all have their own properties in regards to optimum fermentation temperatures. However, most of the beers we see inoculated with any type of "bug" or "wild" yeasts/organisms are typically kept at room temperature (68°-72°F) or higher. So, by the explanation above, these wild and sour beers are widely accepted as ales.

And there you have it!

To recap, ale yeast (Saccharomyces Cerevisiae) and lager yeast (Saccharomyces Pastorianus) is the only physical difference between them. The flavor differences between lagers and ales are small, but noticeable. Lagers are clean, little no no yeast character with and no fruity esters, fermented a cool temperatures, and are submitted to extended lagering. Ales tend to have fruit character, fermented at higher temperatures, and not aged as long by comparison. There are exceptions with hybrid's using lager strains at low ale temperatures or ale strains at high lager temperatures.

Hope you learned a thing or two. Thanks for reading!

Cheers,

Gilbert "Charlie" Perez, Certified Cicerone®