Sanitizing bottles in a dishwasher
Q: I have heard many people talk about sanitizing bottles and have heard different opinions. The two most common opinions are: 1. Never use a dishwasher, always clean with sanitizing solution in a sink. 2. You can use a dishwasher but use high temperature wash/heat dry cycle and no cleaning/sanitizing solution. I know that the sanitizing in a sink works, but I have never tried the dishwasher technique. What do you recommend?
— Chris Vaughn • West Chester, Ohio
A: I have heard the same pearls of bottle-washing wisdom you cite in your question. I have also heard similar suggestions made about all sorts of other bottle sanitizing practices and often find myself wrinkling my forehead thinking, “Well, what do the big boys do?” When it comes to washing and/or rinsing bottles it is indeed helpful to look at what commercial brewers do because they are pretty knowledgeable about washing bottles.
At one time it was common for brewers to wash and reuse bottles. Times have changed, though, and it is nearly unheard of for brewers in certain areas of the world to use returnable bottles. In the US, for example, the use of returnable glass is all but gone. However, returnable glass is still common in some countries and brewers continue to clean all sorts of things off of bottles (inside and out) before filling. Bottle washers are the industrial equivalent of giant, continuous dishwashers. Several stages of cleaning are present in bottle washers, including hot caustic soak sections, caustic jet sections, hot and cold water rinse sections and a final rinse with fresh water. This kind of machine gets the bottle clean. Following cleaning, returnable glass must be inspected for any defects, such as chips and cracks, and most of this inspection is now performed with in-line imaging equipment.
New glass does not have to be washed before filling, and that is certainly one of the appeals of using new glass for a brewer. Whether using new bottles or returned and cleaned bottles, a bottle-rinsing machine is almost always used before bottle filling. Twist rinsers were once common but have largely been replaced with rotary rinsers that have a much smaller footprint. Some brewers use a liquid sanitizer in the rinser to kill contaminants before filling. The most effective sanitizers in this operation are those with a fast kill time and these are usually oxidizers, such as chlorine, ozone and peroxide. The problem with these sanitizers is that they can oxidize beer, especially ozonated water and peroxide solutions, and, in the case of chlorine, lead to significant off-flavors. The preferred sanitizer these days is steam. Steam has a quick kill time when used as a sanitizer, is relatively inexpensive, is easy to control and, provided that the steam is free of contaminants, leaves no residuals in the bottle that affect beer stability or flavor.
So what does any of this have to do with your question about cleaning bottles at home? For starters, it illustrates that commercial brewers use cleaning machinery. So the one camp that says, “never use a dishwasher” is pretty much out of touch with reality because commercial brewers are running specialized “dishwashers” across the globe. The other camp suggesting that it is OK to use a dishwasher as long as a cleaning solution is not used is also a bit out of touch, however. I think both suggestions have merits, but clarification is required.
One of the practical problems with dishwashers is that a dishwasher is not always the cleanest thing in the kitchen. Television commercials showing a dishwasher full of dishes covered in food totally disgust me. I am one of those dishwasher users who loads the dishwasher with very well-rinsed utensils, plates, glasses, etc. If your household has a clean dishwasher, using it to clean bottles is not, in my opinion, a terrible idea. You can always clean the inside of the dishwasher by running it empty and inspecting it after cleaning for any residuals.
When it comes to detergent selection for bottle washing, you want to choose a detergent that is designed to attack the target soil and leaves nothing behind. If you choose an unscented, all-purpose dishwashing detergent you should be fine. I like some of the newer detergents on the market that have sodium bicarbonate (baking soda) as the primary ingredient. Baking soda really is a great cleaner for glassware provided that there is not too much heavy soil, which is something that a homebrewer directly controls.
If you rinse your bottles after emptying for consumption there will be little soil to remove and there is no reason to use an excessive amount of detergent or the most aggressive cocktails designed for a bunch of greasy plates. You probably will find that using half the recommended amount will work just fine for cleaning rinsed bottles. Running a second rinse after the cycle is complete may give you a higher level of assurance that there is nothing on the surface of the bottle. The hot dry cycle will leave your bottles in a clean and dry condition for use. However, if you are packaging carbonated beer you will definitely want to fill your beer into a bottle that has been recently rinsed with water so that the surface is wet; this helps prevent foaming caused by rough, dry surfaces.
Dishwashers do have a pretty bad reputation for destroying clear glasses. I have washed my beer and wine glasses by hand since first discovering the odd odor and appearance of glasses washed in dishwashers. It turns out that glass is etched by soft water when the water temperature is over about 140 °F (60 °C). Since most dishwashers heat water to about 160 °F (71 °C), which accelerates the reaction, this type of glass damage is common in areas with soft water or in applications where water is softened. Hard water may leave a film behind, but hard water spots and films can be removed with a mild acid like vinegar.
If this all sounds like a big hassle, you can simply soak your bottles in a mild detergent, rinse and dry. Whatever you decide to do, though, just make sure you are using clean glass on bottling day.
