Dear Mr. Wizard,

I recently have acquired a keg from a buddy at work. I’m not sure where he got it, but I was wondering if I should pay a welder to cut the top off the keg or if I can do it myself? Also, to add a spigot, does that have to be welded on the keg or could I use something else instead of welding?

Jeremy Sherman
Sterling Heights, Michigan

Mr. Wizard Responds:

Jeremy, this sort of question comes about once a year and when I answer I always “beat up” the questioner . . . so I hope you’re a good sport! Okay, just so I understand, your buddy at work found a “stray keg” that was abandoned at a party or behind some skanky bar and gave this keg a nice warm home in his basement. Now the keg has been donated to you since you are a homebrewer and can put this sad and lonely keg to good use. Is this a decent re-creation of the facts of how you got this keg?

The true owner of the keg does not really care where your friend got this keg. The owners really just want their property returned. Most keg owners do not camouflage their identity to confuse prospective keg users with questions about who really owns the keg, rather they stamp the brewery name on the perimeter of the top (called the chime). Sometimes they even paint their name on the side of the keg. Boulevard Brewing Company in Kansas City, Missouri, has clever stickers on their kegs asking customers to help return lost kegs to the brewery. These stickers also comically explain that keeping one of their kegs is theft.

The reality of kegs is that some are damaged to the point where they can no longer be used and are actually retired. For those readers interested in buying used kegs, start with your local craft brewer. This is a legal way of acquiring property. Many brewers, especially the larger guys who don’t sell their used stuff to individuals, sell used kegs to companies like Sabco (www.kegs.com) who recondition and resell them. Reconditioned kegs typically have the original owner’s name ground off of the chime, especially if they are resold to another brewery. Sabco even sells the parts required to convert a keg into a kettle, and actual keg-kettles.

This is the end of the prelude to the answer to your question and that is about paying someone to do the work versus doing it yourself. I know a lot of folks who work on stainless steel and not one of them would dream of paying someone to do something that they can do themselves. The fact that you ask about attempting this yourself leads me to believe that you have no experience cutting or welding stainless steel.

My recommendation on this project is to have someone do the work for you if you have never done this before. Or, at very least, have someone that does have experience help you do the work. If possible, I would cut off the top with a plasma torch for the smoothest cut that would require a minimal amount of grinding to remove burs and irregularities in the shape.

As far as outlet fittings, you can go with a welded outlet or a bulkhead fitting. A bulkhead fitting is inserted in a hole and sealed with a gasket and nut. The advantage of this style fitting is that it requires no welding and is easy to replace. The disadvantage is that the gasket and nut present a crevice on the inside of the kettle and is not as easy to clean as a smooth, welded connection. I prefer welded fittings for this reason.

If you have the outlet welded to the keg you can either weld a valve directly to the keg or have a fitting welded to the keg. I prefer having a fitting on the keg and then attaching my valve to the fitting. This allows for the valve to be removed for maintenance or replacement if the valve becomes damaged. If you want to use a ball valve with a threaded connection you can have a NPT coupling welded so that it will mate to a ball valve (which are readily available). I have a personal thing against threaded connections and prefer sanitary fittings. I would have a ferrule welded in the keg and attach my valve with a clamp and gasket. This method requires a more expensive outlet valve that is more difficult to find than the ubiquitous ball valve available at every home hardware store.

I hope this information helps in your decision making process!

Dear Mr. Wizard,

I saw the ads for the Coopers carbonation drops and they seem like an easy alternative to the hassle of counter-pressure filling, but here’s the rub: I don’t like that little white layer of yeast in the bottom of the bottle.

I actually like filtration to make my beers fairly clear. Is there a happy middle ground? Is there a beer filter with rougher filtration that would allow just enough yeast through to let the carbonation drops work without leaving the residue in the bottom of the bottle?

Mark Lashway
Moriah, New York

Mr. Wizard Responds:

So you’re one of those picky brewers who wants the best of both worlds! Fortunately, there is a way to have bottle-conditioned beer sans yeast cake, but rough filtration is not the method of choice. Most filters are designed to remove particles above a certain size and not all filters are successful in their duty. You are looking for a filter that removes most of the yeast, say 90%, but allows 10% to remain in the beer — a product like this is not on the market. There is, however, an alternate approach. Some brewers producing cloudy beers, such as hefeweizen, want some yeast in the bottle but not the full load suspended in the beer after aging. A common approach to this quest is to filter or centrifuge a portion of the beer and blend the clarified beer with cloudy beer before bottling the mix. This technique is very easy to setup and can be done inline between the fermenter and bottling tank. To do this, install a bi-pass around the filter or centrifuge where the cloudy beer and clarified beer streams are recombined on the way to the bottling tank.

Another method is to filter the entire fermenter and remove all of the yeast remaining from fermentation and then to add fresh yeast prior to packaging. There are two different reasons for using this method. The first is aesthetic. Some yeast strains are very flocculent and settle in the bottom of the bottle into a tight pack of yeast. If the beer coming out of the bottle is supposed to be cloudy, it may not be if the yeast is too flocculent. If the yeast is disturbed the consumer may see chunks of yeast in their glass as opposed to a uniform cloudiness. Some weizen brewers remove the fermenting strain from the beer and replace it with a less flocculent yeast strain. In fact, some bottled hefeweizens actually contain lager yeast in the bottle since they are typically less flocculent than ale strains.

The other reason to remove the fermenting yeast from the beer prior to packaging is consistency. If I want to bottle condition my beer and control the amount of yeast in the bottle, adding fresh yeast to filtered beer is a very good method of accomplishing these goals. Sierra Nevada Brewing Company uses this method for these two different reasons. Like you, Sierra Nevada wants a very faint film of yeast in their bottles that is almost imperceptible to most consumers. They also want to bottle-condition their tasty ales and do not want to trust this final step of brewing to any old yeast hanging about in the fermenter. Instead, they use freshly cropped yeast with the highest viability for this purpose. This is important since the amount of yeast added is just enough to get the job done, hence the freshest yeast is selected. The yeast concentration in a bottle of Sierra Nevada is about 1 million cells per milliliter of beer. This equates to about 1/10 of the yeast added for primary fermentation. Assuming the same cell density in the yeast slurry is 100 million cells per milliliter (typical for a starter) you need to add 3.5 milliliters or 1/10 of an ounce of slurry per bottle — a very small volume indeed.

The easiest way to do this at home is to begin by growing up your yeast starter. Since you will only need about 200 milliliters (~7 ounces) of yeast you can simply buy a liquid starter if that is more convenient. Then, filter your beer and determine the volume of filtered beer by using a calibration strip on your bottling bucket. This step is important because you are going to add the priming sugar based on beer volume. Add the required amount of priming sugar to the bucket along with the yeast. The amount of yeast can be easily estimated by dividing the beer volume by 100. If you have 5 gallons (18.9 liters of beer) you will need 0.05 gallons (0.189 liters) of yeast slurry. Mix up everything and bottle.

One word of caution about beer handling in general is oxygen pick-up and its affect on beer oxidation. Minimizing air pick-up during racking is key and especially during filtration since yeast, which is a good oxygen scavenger, is removed. The small amount of yeast added in the method described above is insufficient to prevent oxidation and care must be taken during the process. Carbon dioxide blanketing and measures taken to prevent splashing are both recommended.

So now you can have your cake and drink it too!

For more of the Wizard's wisdom, pick up the latest issue of Brew Your Own magazine now available at better homebrew retailers and newsstand locations.