Preservation and refrigeration

I think that @JackHorzempa has both an answer and a table which shows useful information.

BTW, the temperature does not create skunking. That only comes from exposure to light.

 

I am assuming you mean stale flavors vs. skunked here; for a beer to get skunked it needs to be exposed to UV (e.g., sun) light.

Below is a handy graph to demonstrate how cold storage yields a longer shelf-life for beer. For those unfamiliar with the Celsius scale, 20 degrees C = 68 degrees F and 10 degrees C = 50 degrees F.

Cheers!

 

Reason #83 to hate best-by dates.

We're nearly always guessing whether or not that means refrigerated, cellar, fermentation, room, or whatever temp.

 

It's not the alcohol that stales, it's the other ingredients in the beer. Hops are notorious for degrading fairly quickly, and other ingredients have varying degrees of degradation speeds. Dark beers (mostly) with an ABV of 8 percent or so can age nicely and improve at the same time. And storage conditions can have a significant effect on all of the aging process, good or bad.

 

Well, I can report what AB does here. They actually test how their beers taste over a period of time. They then evaluate how the beer (e.g., Budweiser) tastes on a scale of 1-10 (with 10 being factory fresh). They have determined that after 110 days a beer like Budweiser is a 7 and this is what they deem to be unacceptable for sale.

I have not heard of any other similar taste testing by craft breweries but it would not surprise me that some do something similar.

Cheers!

@RobH @sierranevadabill @Sixpoint @StoneBrewingCo

 

Once again, this varies. Some brewers take it very seriously with testing and others will simply put a date on it.

 

PhotoScape is my friend. Here is the Fahrenheit version for those of us Celsius challenged.

 

Two thoughts come to mind:
The 0 on your temp scale s/b 32
Storing beer at 32.000001 degrees will provide optimal (non aging) conditions.

Why doesn't everyone do that?

 

To broaden that question to: Why doesn't everyone store beer at refrigerated temperatures?

The answer is pretty simple: money.

Cheers!

 

@JackHorzempa can you define what staleness refers to in the diagram? While there's a pretty clear definition of skunked (e.g. the chemical reaction of light with beer) there doesn't seem to be a clear definition of stale. Doing a quick google search I see some articles that talk about oxidation which slows down when a beer is stored cold. I'm hoping you can clarify whether the diagram is based on that or something else. I doubt oxidation because that should be dependent on the canning or bottling process as well. Refrigeration also cuts down on effects such as wild fermentation from cross contamination I believe which would have helped with beers such as BCBS last year I believe. Certain aspects of beers will fade regardless of storing them cold such as hoppy IPA's (especially those with dry hopping). Many dry hopped IPA producers recommend storing cold always but I haven't really seen a definitive study that shows that a dry hoppy beer still tastes hoppy longer when stored cold. Hop oils will break down I would presume faster in warmer temperature but my understanding of dry hops is more related to them being suspended in the beer which may not be affected by temperature. Its also not clear whether the graph is affected by a beer being pasteurized or not. Thanks.

 

Because the moment the beer leaves the brewery in a distributors truck, all the majority of them can do is strongly imply how it is kept. If the beer has to move across state lines and be handed off between distributors with distinct territories. You are entering a big variable into the equation where beer can sit out in the sun, or sit in a stuffy warehouse, or be in a non reefer truck.
If it's a brewery that ships a little. It can easily get lost when there are 5000+ other breweries fighting the same battle. A distributor would much rather deal with volume than dribs and drabs. And if the brewery can only afford to pay for one sales person for a wide territory, or a whole state. They can't do ride alongs to a majority of the accounts which get the beer and keep it willy nilly. So they focus on the ones that do volume.

 

I can't say with certitude what the 'author' of this graph means by staleness. In general staleness can mean a number of things under two classes:

• Development of off-flavors. One of-flavor that you may read in BA posts is cardboard like flavor due to the development of a chemical compound of trans-2-noneal. This compound is developed as an oxidative process.
  
• Loss of desirable flavors. You will read a lot on BA about how hoppy beers lose hop aroma/flavor with age.

All chemical processes slow down with colder temperatures. Oxidative processes slow down with cold storage. Other (non-oxidative) chemical processes slow down with cold storage. All staling proceses are due to chemical processes but the oxidative processes are most worrisome to beer scientists.


Below is an extract from the Brewers Association booklet entitled Best Practices Guide to Quality Craft Beer - Delivering Optimal Flavor to the Consumer.

“How to Know if a Beer is Stale

“Stale” is not a specific, consistent off-flavor. It has different characteristics depending on beerstyle but broadly (compared to fresh beer flavor) we can note:

• Slightly staled – Ribes flavor (characteristic note of blackcurrant leaves and stems and associated with high headspace air content – also described as “catty” and like tomato plants. Found in the early stages of oxidation), cardboard impression, loss of estery notes, and astringent bitterness. (See Table 1 for further definitions.)

• Staled – Bready flavor notes, changes in body or mouthfeel, and harsh bitterness.

• Very Stale – Honey-like flavor, decomposed bitterness.

• Extremely Stale – Sherry. (Later leathery notes may appear.)

And in relation to specific classes or styles:

• Lagers – Increase in sweet, stale (ale) papery/cardboard and metallic notes. But alcoholic, floral, and DMS (dimethyl sulfide) (See page 11) characteristics decrease.Become less lager like—more ale-like.

• Ales (low gravity) – Ale character retained but is diminished as sweet (molasses), dried fruit, cheesy, and, in extreme cases, catty fl avors arise. Perceived estery aroma and flavors decrease (due to masking rather than physical diminution). Vinous (wine and sherry-like) notes may appear.

• Stouts – Oxidation damages malty and caramel notes. Cheesy notes may arise as well as stale flavor.

• Strong beers – Quite flavor-stable, relatively speaking. Do not develop the papery, leathery, and metallic notes common in lower strength beers. Caramel, licorice, and astringent flavors are increased. Alcoholic and burnt notes change. In general, it seems stronger beers mellow (get smoother) with age. But as yeast cells age and die, they can autolyze, giving rise to salty, soy sauce-like/MSG notes. These notes have interesting effects on overall flavor and may not all be regarded as bad.”

Cheers!

 

I am not sure how to comment to the remark of "definitive study" but I would recommend you read:

http://www.pastemagazine.com/articles/2014/06/beer-is-the-new-milk-drink-it-fast.html

As to pasteurization, this process 'kills' bacteria which can spoil beer but pasteurized beer will go stale just like unpasteurized beer does. AB pasteurizes bottles/cans of Budweiser but they give that beer a shelf-life of 110 days. It seems to me that this graph is agnostic as regards pasteurization.

Cheers!

 

Thanks for both responses, very informative. I recall reading some articles like you mentioned now regarding IPA's. So perhaps not "definitive" but good enough info

 

Good point, forgot to change 0 to 32! Now fixed above.