I would like some information on methods for cleaning and sanitizing bottles. Also what is the best way to store the bottles after they are cleaned/sterilized? We like to reuse our bottles but want to make sure they are properly sterilized before each use.
San Antonio, Texas
Let’s start with brand new bottles that your local microbrewery buys. These bottles arrive from the supplier clean and packed in various ways. Whatever the delivery package, the clean glass is brought into the package line where the bottles are rinsed with clean water. Rinsing removes dust, wets the surface, and readies the bottle for filling. The key thing with rinsing a bottle before filling is that wet bottles are a lot easier to fill than dry bottles because the wet surface is much less likely to cause foaming. This is something that is also applied when filling beer glasses.
Some, but not all, breweries add a sanitizing compound to the rinse water. Common sanitizers include ozone, chlorine dioxide, sodium hypochlorite (bleach), iodophor, and peroxyacetic acid. These sanitizers are often added more to keep the water clean than to sanitize the surface of the bottle, but some breweries do indeed rely on liquid sanitizers to sanitize the bottle surface. All of these compounds can cause flavor problems in the beer if much remains on the bottle surface and modern bottle rinsers are designed to minimize the volume of rinse water left on the bottle surface. Dilute bleach water works great at home as long as the sanitizer is allowed to completely drain and dry from the bottle before filling.
The reason I wanted to cover how commercial breweries handle glass is to illustrate two key points. The first is that starting with clean, new glass is the norm and the second is that there is not much that is done to sanitize the glass other than rinsing the bottle with a relatively dilute, no-rinse sanitizer.
What about breweries who use returnable glass? This practice is actually on the decline in a major way in many beer-drinking countries, and is pretty much not seen in the US. But for the breweries in other countries that use returnable glass, the process begins with used bottles in all imaginable forms of dirtiness arriving at the brewery. These containers need to be freed of their labels, cleaned and sanitized before use. Strong, hot, alkaline (caustic) solutions are the primary cleaner and this intensive process effectively cleans and sanitizes the bottles. The cleaning also slowly etches the glass surface, making returnable bottles easy to spot due to their less-than-new appearance. The rest of the packaging process is pretty much the same, except that special care is taken to screen empty and full bottles for chips, cigarette butts, and other stuff that may be left in a bottle after cleaning, imperfections, and cracks using in-line scanning equipment.
Homebrewers have the same options as commercial breweries; new and used glass. My recommendation is to buy new bottles from a local homebrew supply retailer, care for them like you would drinking glasses and enjoy a long service life. This means rinsing your new glass with a dilute sanitizer for the first use, allowing the sanitizer to drain, and filling. Bottle trees, whether purchased or homemade, are very handy when it comes to draining your rinsed bottles. Unless you are packaging carbonated beer using a counter-pressure filler there is nothing wrong with performing the sanitizer rinse and drain step before packaging, and then storing the bottles until bottle day. The easiest way to store clean glass is in a clean case box with a plastic film covering the bottle tops, or storing the glass upside down in a clean box lined with a clean sheet of foil or butcher paper.
When it comes to collecting your bottles for use in the future, I strongly recommend being particular about things. Soon after emptying a bottle you should thoroughly rinse the glass, making sure to remove any yeast sediment, and set it aside for further cleaning in the future. When you have accumulated enough bottles to hold a batch you can clean the bottles for re-use.
It is really tempting to use a dishwasher to clean bottles, but you should resist the temptation. I mentioned earlier that commercial bottle washers cause glass etching. The same thing happens at home. Dishwasher detergents are formulated for use with soiled dishes and are very aggressive on pre-cleaned dishes. I am a pre-cleaner because I cannot stand to look at a dishwasher full of nasty dishes. I learned a long time ago that putting my beer and wine glasses in the dishwasher is a bad thing because they are etched and develop a weird aroma when repeatedly washed in a dishwasher. I baby my glasses and any bottle that I plan on re-using. Dishwashers can be run without detergents where the dry cycle is used to heat sanitize your glass.
Beer bottles do not contain any heavy soils, as long as they are carefully rinsed after use, and mild dishwashing soaps or bar-type cleaners work very well. One of the old-fashioned glass cleaners used in bars is sodium carbonate. This is a mild alkaline cleaner that does a great job on glassware. A bottle brush can be used or you can simply soak your bottles in a hot cleaner for several minutes (time depends on cleaner, temperature, and soil load) before rinsing. Once the clean bottles have dried you can rinse again with your sanitizer solution.
Some brewers hike their concerns about sanitizing glass up a notch when brewing lower alcohol beers since they are more prone to microbiological spoilage. I honestly do not get too worked up about glass sanitizing as long as good cleaning procedures have been used on bottles that have been previously filled and emptied. I hope this information is sufficient to answer your question and that you confidently move along with your bottle washing plans. My answer to your question is complete, but I am not done writing!
When I was a first-year graduate student in Dr. Michael Lewis’ brewing lab at UC-Davis I was given the basic lab rules from a senior student in the lab. This was in 1991 and we had ready access to returnable longneck bottles. We obtained most of the glass for lab beers by buying cases of empties from the local Budweiser distributor and bringing them into the fold. We used caustic to soak the labels free from the bottles, put the bottles in a laboratory dishwasher with a heavy duty glass cleaner (that eventually pitted the surface of the bottles) and sterilized the bottles in a steamer. After doing this for some time using the same bottles over and over we began having bottle explosions during bottling. I don’t like exploding glass, even when wearing a full-face shield, and decided that steaming clean beer bottles was a wee bit excessive. We discontinued the practice, stopped seeing bottle bombs, and never had any issues with contamination associated with our glass.
My point to this whole story is that there is a downside to overkilling your process. The biggest battle with removing microbiological contaminants from a food contact like glass or stainless steel is cleaning it. Sanitizing is pretty easy after you have successfully cleaned the surface, and ambient, dilute sanitizers work quite well on clean glass bottles. Gotta quote Charlie Papazian on this one … “Relax, don’t worry, and have a homebrew.”
In Designing Great Beers, Ray Daniels shows how to build a grain bill using a 5.5-gallon (21-L) example. How can you use his technique to brew a single-gallon (4-L) batch? Will you encounter any issues by just dividing all of the listed ingredients accordingly?
William Joe Elliott Jr.
I have been designing beers using math since I first learned how to calculate a brew 25 years ago. There is something rewarding in the formality that goes into crunching numbers and coming up with the recipe on paper that is used as the brewing road map for wort production and the all-important start to something [hopefully] wonderful to follow. If a mathematical brewer is handed a recipe, the first thing they will likely do prior to brewing is to check the math and adjust the recipe for their system. That’s just how some brewers are wired. But beyond the basics of correcting for brewhouse efficiency and anything one actually knows about their hop utilization no real magic comes from this exercise.
Hand me a recipe for a batch of a given size, ask me to scale it to another size and the most direct method is to simply scale the recipe proportionally by volume. The recipe is a road map and leads us in a general direction. Brewing great beer requires much more than a recipe and the greatness usually comes from tweaking a brew with repetition.
It’s been a while since I have taken a musical digression and this is a pretty good topic to lead me down my favorite rabbit hole. My musical life is lived vicariously through talking to musicians and my friend Brandon allows me to stay connected to my favorite jazz instrument, the saxophone. Brandon plays an early ‘60s Selmer Mark VI tenor named Bessie. Her lacquer is worn thin and she sports a gorgeous patina associated with age and dignity. Bessie is the type of tenor that young tenors look forward to becoming after years of being played by great musicians. These days Bessie is played with an Otto Link mouthpiece and medium hard reeds, the same set-up used by greats like John Coltrane and Dexter Gordon. Brandon is a great tenor player and has his own sound and techniques to produce his sound. Yeah, his tenor rig is the same basic set-up used by many great jazz tenor players but the instrument is just a piece in the sound puzzle. When a musician reads music and plays the tune they are reading, the tune is going to sound different when played by another musician using the same or similar instrument.
Very few brewers, whether homebrewers or pro brewers, have the same brewhouse and will likely produce different beers from the same recipe. The reasons for this are entirely different from my musical parallel. Most brewing recipes provide a general guideline of malts, hops, brewing water, yeast, mash method, boil time, fermentation temperature, clarification method, aging duration, and packaging specifics. It’s hard enough for brewers to brew the same beer time after time using the same equipment and actually knowing the specifics of ingredients and process. Two brewers using different equipment to produce the same beer is very difficult, and two brewers using different equipment and different ingredients to produce the same beer is virtually impossible. The batch size really pales in comparison when put into the context of all of these variables.
A brewing recipe is a road map. If you are proficient in brewing calculations, which by no means is a requirement to brew really good beer, the things that you can do to reconcile a recipe is confirm that the malt bill is going to give you the wort OG (original gravity) specified by the recipe. Wort gravity is a major driver of flavor and body and it really helps to nail your target OG. Checking the bittering calculations is also helpful, but in my opinion calculated bitterness tells me very little about how bitterness will be perceived in a beer. And the truth is that very few homebrewers and small commercial brewers know anything at all about their hop utilization rates, meaning that most hop calculations and published IBUs are fancy approximations.
Use that recipe as a road map, evaluate the finished beer, make adjustments and keep brewing until you come upon the right beer. I truly believe this is the art of brewing. Tweaking the recipe includes playing with different malts, using different hop varieties and hopping rates, playing with the water chemistry, and pushing the fermentation in different directions. After a recipe is used for the first time and tweaks to the recipe are made, the recipe is now yours. Happy brewing!
I brew on a 1⁄2-barrel Heat Exchanged recirculated mash system (HERMS). I turn up my hot liquor tank (HLT) temperature to about 200 °F (93 °C) for recirculating the wort. If I don’t keep the HLT temperature that high it takes forever to bring the mash temperature to my target. Is keeping it this hot affecting my efficiency?
Paul, the direct answer to your question is “no”; using 200 °F (93 °F) water to heat wort with a copper coil heat exchanger is not going to hurt your efficiency. The important factor is the wort temperature measured at the outlet of your heater, not the temperature of the heating medium.
Heat transfer rate is defined by the following simplified equation:
q = UAΔt/d
Where “U” is the overall heat transfer coefficient, “A” is area, “Δt” is the temperature difference between the heating medium and the product being heated, and “d” is the thickness of the heating surface. This basic equation is used in all sorts of engineering applications from home insulation to food processing to power plant operation. There are a few important take home points that are very helpful to brewing since heat exchangers are used for mash and wort heating, water heating, wort boiling, wort cooling, and fermenter control.
The easiest ways to increase the overall rate of heat transfer are to increase the heat transfer area and/or increase the temperature of the heating medium. In the case of HERMS mashing, you can increase the heating area by using a longer heating coil or by changing the diameter of the tube (tube area = πr2L, where r is the tube radius and L is the tube length). At home it is not practical to use tubing that is greater than 1⁄2 inch (1.25 cm) in diameter because anything larger is difficult to bend without purchasing special tools, and extending the tube length is limited since the tube coil needs to fit in your hot liquor tank.
If area is effectively maxed out, the next variable to play with is temperature. The challenge with this is that water can only be heated to 212 °F (100 °C) before it begins to boil. This limitation can be overcome by using pressurized hot water systems, hot oil systems, hot glycol systems, or steam systems. Pressurizing water above atmospheric pressure increases the boiling point and is really simple in principle, but has several challenges related to safety and practicality. Steam systems are the norm for commercial breweries, but very uncommon at home because of cost.
I don’t know of any homebrewers using hot oil or hot glycol systems, but these two heating media can be heated well above 212 °F (100 °C) and used in the same fashion as the water in your hot liquor tank. In fact, if these high temperature fluids are pumped through a coil submerged in a kettle they can be used for wort boiling. Commercial hot oil and pressurized water brewhouses were fairly common from the 1950s through the 1970s, but were replaced by steam systems. Although this solution requires another vessel and pump, the design is really pretty simple and may be of interest to some.
The third approach is to focus on the U-Value. So what is the U-Value? It’s a term with multiple components that essentially describes the resistance to heat flow of the heat transfer surface. In the case of a heat exchanger tube, the primary components of the U-Value include:
• The thermal conductivity of the heating surface.
• The convective heat transfer coefficient on the product side of the tube.
• The convective heat transfer coefficient on the utility side of the tube (hot water, oil, etc.).
The U-Value is adversely affected by fouling at the heat transfer surface, and the take home message is that a dirty heat exchanger performs less effectively than a clean heat exchanger by reducing the convective heat transfer coefficient. Soils on the wort side and mineral deposits on the utility side are examples of fouling that brewers must address to prevent progressive reductions in heating rate.
The thermal conductivity of the heating surface is a material property and copper conducts heat at a rate roughly 17 times greater than stainless steel (assuming the same material thickness). Although stainless steel has many advantages over copper, thermal conductivity is not one of them. As long as you use cleaning chemicals that are compatible with copper, you will get a very long service life from your heating and cooling coils. The bottom line with this topic is that material selection directly influences the U-Value.
Finally, there is the convective heat transfer coefficient. The most effective means of increasing this value is with liquid turbulence at the heating surfaces. With a HERMS the wort is pumped through the heat exchange coil. Turbulence can be increased inside the tube by increasing flow rate for a given tube size or by reducing the tube size for a given flow rate. Turbulent flow is defined by the Reynold’s number, where Re = ρvd/µ and Re>4,000 is defined as turbulent; ρ = density, v = velocity, d = diameter, and µ = viscosity.
In your HERMS, the hot water in your hot liquor tank moves very little, and the movement that is present is entirely due to natural convection. Stirring the water will significantly increase the U-Value by changing the convective heat transfer coefficient on the water side of the tube. Water tanks can be stirred with a simple mixer or by pumping the water in the tank and returning the water at an angle that causes movement. In the case of a tube-in-tube heat exchanger, such as a wort cooler where a copper tube is surrounded by a hose, the water side convective heat transfer coefficient can be affected by playing with the Reynold’s number.
At the end of the day, what matters to the enzyme system in the mash is temperature. How you change the temperature affects heating rate, and as long as you don’t increase the mash temperature by heating wort from the mash to very high temperatures you will be in good shape.