View Full Version : keg storage

12-02-2005, 11:00 AM
I'm wondering what is the optimal temp to store kegs at, full of course. I guess I'm a little confused as to why many brewers and wholesalers store their bottles at room temp and kegs in a cold room. Why not both at room temp (60-75)or both in cold room. Just trying to figure out storage issues.



12-02-2005, 11:56 AM
The big companies typically pastuerize their bottled and canned products, so they have a longer shelf life at room temperature than an unpastuerized keg. The bad news for craft brewers is that many retailers treat craft beer the same way, bottles (or cans) on the shelf at room temperature, when in fact they should be refridgerated.

12-05-2005, 06:11 PM
Don't forget that some breweries bottle condition and would need to store beer at a happy ale yeast temperature. Maybe you've seen this? I'd vote best to store at the temp you age at.

Diamond Knot
12-06-2005, 02:35 PM
Unless you pasteurize your beer...........even if you bottle condition..........I'ld store at the coldest temperature possible to 33F. There are still little beasties in there that can make a fine bottle of vinegar out of your fine brew over time. We only keep our beers warm for dry hop aging on those we do dry hop and refrigerate the rest.

Just my $.02

01-28-2006, 09:45 PM
K, Kegs can be pasteurized, which would allow them to be stored at room temperature. I make this comment becuase in other areas of the world this is the practice, driven by necessity.

There are a few comments that should be made relative to the process which happens to a bottle vs keg.

Pasteurization protects flavor and foam against changes in temperature. We all have the stigma that it is "OK" to leave a bottle at room temperature becuase we see a number of brands which have been and are legitimately offerred that way on the store shelves. Pasteurized products can handle these conditions. Often we see unpasteurized products treated as if they are in the stores. This is wrong. The writer above said it correctly, these beers should be kept refrigerated.

When a brewer pasteurize their bottled production, they are filtering and doing a carbonated fill at approximately 33 degrees F. They are not doing bottle conditioning. Generally, larger brewers pasteurize through a tunnel pasteurizer on the packaging line. The tunnel pasteurizer accomplishes three functions.

1. It does the pasteurization process in the bottles by killing bacteria in the beer and effectively stopping fermentation. For this reason bottle conditioning and pasteurizing are mutually exclusive.

2. The pasteurizer discharges the beer at a temperature high enough to prevent bottles from sweating. Sweating can create havoc on corrugated cartons and boxes, and can impact label application quality. A good BOT (bottle out temperature) is 75-85 degrees F.

3. Process Stability - As pasteurization happens after the beer is already in the package, the bottle, the cap, and the product are pasteurized together. If there had been a mold spore present on the bottle cap, it is no more when a proper process is complete. If you picked up some bacteria in a valve or a hose since last batch, same applies. Again, these are bottles which are filled and capped going through the tunnel pastuerization process. The product output between batches becomes more consitent. Fermenation stops, and most chemical reactions stop at the same time on each batch.

Again, tunnel pasteurization is done by some brewers. Beer rarely goes "bad" like milk would if it were not pasteurized. What happens is that flavor stability becomes very temperature sensative. Some of the product that we see on the store shelves at room temperature has not been treated for that condition, which can result in a degredation of flavor and foam. Over pasteurizing can give a burnt or "carmalized" taste to beer, so it has to be considered well when you are doing it.

That is the background on bottles. Now for kegs.

Kegs are generally in (North America) filtered, carbonated, and kept cold through the distirbution chain, but options are available, but you may conclude that those options are not too appealing.

Beer in a keg could be pasteurized differently. In this you would consider flash pasteurization. In flash pasteurization the beer is heated in the pipe to a very high temperature for a very short duration of time to kill bacteria and effectively stop fermenation, and cooled down and delivered to the keg. It is done in this fashion becuase heating the complete keg would consume an inordinate amount of energy.

Unlike in the process used with bottles, however, the keg itself is not "pasteurized" in the process. You have to remember that there are pipes, valves, concievably hoses, etc. and the keg, bung, what have you where contaminents could be introduced in your process. Unlike in tunnel pasteurization (which kills everything inside the package) if you had contaminent introduced after the pasteurization is complete, the effect of that contamination may not (and likely would not) be known until that keg is in the market.

Bear in mind, like bottles there is no option for pasteurizing and "keg conditioning". If you have filtered and pasteurized, you have eliminated the yeast from the product. The only option for adding CO2 is to inject it. In order to fill a keg with CO2 rich product, you need to be filling at about 33 degrees.

There are brewers for kegs who flash pasteurize sterile kegs. They generally store them in some degree of "cool" at the brewery, but when they put the keg on a truck, in many cases it is not a conditioned truck, and the keg is out of their control. It can be done, but it is not generally preferred.

It would be essential that the keg sterilization system you use was thorough and reliable, and as well the area, practices, and methods of filling are not creating opportunity for contamination. Again, this is done of necessity in many areas of the world. If you lived in the Carribean or a warm remote area in Austrialia, you might not have a choice.

Remember, much of the "beasties" in the beer thrive on warm temperatures, and if they do exist, often can grow logrithmically (i.e. they double in a period as opposed to just getting a little bigger...etc.).

Tunnel pasteurization of beer in bottles has a higher degree of "confirming" the stability of the process, than you would have with a keg.

Hopefully that helps with the dilemma about kegs cold vs. bottles warm, and why / how it applies to kegs. Hope that helps.

01-29-2006, 06:10 AM
K, Kegs can be pasteurized,
You can not pasteurise draft beer. It is a federal regulation! But you can micron filter it!

01-29-2006, 12:30 PM
Wow, that's nuts! Doug, where did you find that?

01-29-2006, 02:15 PM
The temp should be kept cold but there are economics to consider. A good range is 40-45 degrees F. Oh pastuerized beer should be kept cold, since this process only prevents microbes from growing. Any beer will degrade faster with temp and movement. In the case of beer in kegs the rule of thumb was that it was traditionaly unpastuerized, but this is why the flash pastuerizer was invented.( ask Jeff Gunn IDD) Several breweries flash pastuerize there keg beer and I havent heard anyone stating a difference between keg and draft.
Hope this helped
good luck

01-30-2006, 03:34 AM
updated circular on draft beer (http://www.ttb.gov/publications/ind_circulars/archives/1965/industry_circular_65-01.pdf)
I guess I had old info. But this explains the whole draft beer label requirements.

02-01-2006, 10:01 PM
Wow, Now that energy is becoming an ever increasing problem and cold storage and shipping charges are continueing to rise, perhaps the time has come for the Sankey keg to find its true place in the USA brewing industry.

The Sankey keg (NOT the side bung conversion) was developed soley for the purpose of flash pasteurizing the beer and putting it into the keg under sterile filling conditions in the UK during 1957. The USA was one of the last major markets in the world to convert to the Sankey system. I joined the Sankey development group in early 1963 and is the reason I came to the USA when it was first introduced into the major brewery groups.

The Sankey keg to this date is still the only returnable aseptic container on the market and is only fully utilized in this way by a handful of brewers.

Flash pasteurized beer put into a Sankey keg on the correct washing, sterilizing and filling system will stay microbially free at room temperature until tapped. I have had beer and wine in kegs for over two years without microbial spoilage. OLD but microbially free. Most microbial problems occur after tapping the keg.

There is NO flavor change with correctly flash pasteurized beer in keg.

I still give the guarantee to my clients that during a triangular blind taste test they can taste the difference between the beer flash pasteurized and kegged on my systems compared to the same beer batch unpasteurized, I will give them the system. Never failed yet.

Ask Graydon Brown - he has tried it and used more than one of my systems.

If you would like my articles on the subject presented to the MBAA and Craft Brewers Conference in past years please email me and I would be pleased to forward it to you in PDF format.

Jeff Gunn
IDD Process & Packaging, Inc.