What is Brass?
In order to understand the risks associated with using brass beer brewing components, we have to learn a bit more about this alloy.
Brass is an interesting combination of metals. It is mainly 55% to 90% copper that has 10% to 45% zinc added to it. Sometimes there can be small amounts of other metals such as aluminum, tin, or nickel added as well. It has been used for many different purposes throughout the years and the other metals added to the alloy can give brass some very interesting characteristics.
According to Columbia Encyclopedia:
“In general brass can be forged or hammered into various shapes, rolled into thin sheets, drawn into wires, and machined and cast. Its ductility reaches a maximum with about 30% zinc and its tensile strength with 45%—although this property varies greatly with the mechanical and heat treatment of the alloy. Cartridge brass (70% copper, 30% zinc) is used for cartridge cases, plumbing and lighting fixtures, rivets, screws, and springs. Aluminum brass (not exceeding 3% aluminum) has greater resistance to corrosion than ordinary brass. Brass containing tin (not exceeding 2%) is less liable to corrosion in seawater; it is sometimes called naval brass and is used in naval construction. Dutch metal (80%-85% copper, 15%-20% zinc) is used as a substitute for gold leaf. When iron is added to brass it produces hard, tough alloys. One of these is delta metal (55% copper, 41% zinc, 1%-3% iron, and fractional percentages of tin and manganese), which can be forged, rolled, or cast and is used for bearings, valves, and ship propellers.”
Often, however, lead is added to the mix to make the resulting metal a little more machinable. Government regulations require that there be less than 8% lead content in brass and it is this lead content that is of the most concern to us as home beer brewing aficionados.
Is the Lead Dangerous?
Now that we know what brass is comprised of, it is up to us to decide if there is really enough lead added to the metal for us to be concerned. It is important to note that it is only the surface metal that poses a threat. And even then, it is only the surface metal that is in contact with consumable liquids that we need to worry about. It is often suggested by fellow home beer brewing hobbyists that all brass components in your beer brewing system should be treated with a special solution in order to remove surface lead and oxidation. This process, which is known as “pickling,” has been around for hundreds of years. Brass foundries in the 1800’s used to pickle metal in order to remove the surface oxidation, artists have used the technique to clean metal components without the use of scrubbing and abrasion, and people even use pickling to clean away solder and flux residue on metals. The question remains, however, if brass components are approved for potable water purposes, is it necessary to perform this procedure?
The EPA suggests testing well water that contains brass underwater pumps just to make sure that the lead level in the water is less than their 15 parts per billion level requirement. They have found that brass continues to leach a small amount of lead into the potable water source throughout the course of its life. Therefore, the lead content of brass seems to be a valid concern with the governmental powers that look into such matters. Couple this with the fact that potable water does not have the acidity of hot wort, and it may become a more valid issue to the home brewer. The best solution, of course, is to use stainless steel or food grade plastic pieces in your brewery. If you are like me, however, you are not made of money and cannot afford to do this. I was forced, due to financial requirements, to use brass fittings in my home brewery and I believe that the lead level on the surface of brass brewery components is pretty minimal and should not be a major concern. Having said that, I have, however, performed the pickling procedure on every brass piece in my home brewery just to be safe. If you haven’t pickled your existing brass brewery components yet, there is no need as you have already stripped away the surface lead with hot acidic wort and it is not necessary to perform the procedure now unless you have done something to expose new surface brass. So, if you decide to perform the pickling procedure yourself on your new brass brewery fittings, how would you proceed?
Pickling Beer Brewing Components
Pickling usually involves the use of an acid. Some common commercial pickling solutions for brass contain sulfuric acid that is diluted with water in a ratio of 1 part acid to 7 parts water. This is a relatively slow pickling solution and it must be noted that you must only add acid to water and not the other way around or you can end up with a very dangerous situation. An even faster pickling solution that is commercially available contains nitric acid that is mixed in a 1:1 ratio with water. Pickling occurs very rapidly with this type of solution and it must be noted that the reaction takes place much faster than what we need for our home brewery situation and in fact the surface of the metal can actually be pitted when you perform this process. There is, however, a very safe and easy method the home brewer can use in order to accomplish the same task.
Beer Brewing Brass Pickling Recipe
The most commonly used method for pickling brass by the home beer brewing community is to mix together a solution consisting of 1 part Hydrogen Peroxide with 2 parts White Vinegar. Submersing your brass components in this solution will effectively and safely remove the surface lead and the oxidation that is present on the metal. The process only takes about 5 minutes and works very well, although agitation of the solution will speed the process. It leaves the metal a nice dull yellow color. If the solution turns an aqua color, it must be discarded and a new batch mixed in order to continue. Don’t leave the parts in the solution for too long or you will end up with a black piece of brass and you will have to scrub the piece clean and begin the procedure again. The advantage of this system is that it is hard to ruin the parts you are using as long as you are paying attention. Thoroughly rinse away the pickling solution with water and allow the pieces to dry completely before using them.
It may not be imperative to use the above pickling procedure, but I found that it at least eased my mind concerning the lead question. I hope that the above text will at least give you the information necessary to proceed with constructing your home brewery safely. Personally, I found that there was not enough information available concerning surface lead on brass beer brewing components and hope that the information compiled here will help you make an informed decision about whether to use them.