Homebrew Lab Equipment
Homebrewing can be as simple or as complex as you make it. Some brewers just follow the directions on their extract kit. Others make up their own recipes and fine-tune their brewing procedures in an effort to brew superior beer. Whatever your attitude
towards brewing, there is a set of lab equipment for you.
Having the proper instruments to measure key brewing variables allows you to repeatedly brew great beer. Equipping your lab can cost as little as $15 for the essentials, or hundreds of dollars for a full-blown mad scientist set-up.
Lab Equipment for Every Brewer:
There are three tools every brewer should use every brewing session: a hydrometer, a thermometer and a brewing notebook. Without them, it would be difficult to consistently brew good beer.
Hydrometer:
A hydrometer is a floating instrument that measures the density of a solution. Brewing hydrometers typically give units of specific gravity, degrees Balling, and potential alcohol. To measure specific gravity, the hydrometer is floated in a test cylinder with the solution to be tested. The hydrometer is read by determining what the scale reads at the level of the liquid.
The wort or beer sample should be at 60° F when a reading is taken. If you have a beer pitcher handy on brewing day, fill it with ice water and use it to quickly cool down wort samples. If the wort is hotter than 60° F, the hydrometer will sink farther than normal into the wort and give a lowered gravity reading. If the wort is too cold, the hydrometer will ride high and give a high reading. There are conversion charts that correct for temperature; ask at your local homebrew shop.
If bubbles stick to the hydrometer, they will cause it to ride high, giving a high reading. To get rid of bubbles on the hydrometer, just give it a spin. The bubbles should fly off the glass. If you are measuring the gravity of a finished beer, bubbles can be a major problem. To deal with bubbles in a finished beer, you should decarbonate it first. The American Society of Brewing Chemists recommends this method: Pour the beer back and forth between two containers (like a pitcher) a total of eight times.
There are several times during a brew session when taking a gravity reading is useful. For all-grain brewers, measuring the gravity of the final runnings can tell you when to stop sparging. The general rule of thumb is to stop before the gravity drops below 1.010 or 1.008. Below this gravity, tannins are extracted. Excess tannins in your wort can make your beer taste astringent. Taking the gravity of your wort before the boil starts can tell you if you will hit your target gravity. To estimate your original gravity at the beginning of the boil, use this equation:
Original Gravity Equation:
OG (original gravity) = [BBG (before boil gravity) * BBV (before boil volume)]/ABV (after boil volume)
Use only the decimal portion of the gravities when using this equation; for example, use “55” for a beer with an original gravity of 1.055. When using this equation, you will slightly overestimate your OG. The OG is overestimated because dissolved proteins and lipids figure into the pre-boil gravity. These compounds, however, sediment out of the wort during boiling. This results in a lower gravity than you estimated.
If your gravity is too low, you can add malt extract. 13/4 ounces of dried malt extract will raise the gravity of five gallons of wort by approximately one gravity point. If your gravity is too high, you can decide to make the batch size larger by adding water. Alternately, you can adjust the hop addition to compensate for the heavier wort.
It’s always best to check any piece of brewing equipment to see that it is reading right. At 60° F in pure water, the hydrometer should read 1.000. If it does not read 1.000, note how far it’s off and take that into account when taking your readings. For example, if the hydrometer reads 0.098 in water at 60 degrees, add 0.002 to all your gravity readings.
Thermometer:
Thermometers come in many shapes and sizes. There are bimetal dial thermometers, liquid (mercury or alcohol) probe thermometers, digital thermometers, and temperature strips that change color. Although different in form, they all do the same thing — measure temperature.
Like hydrometer readings, there are several times in a brewing session when it is useful to take a temperature reading. For all-grain brewers, the temperature of each mash rest is important.
If the mash is not at the correct temperature during the starch conversion rest, the amount of sugars extracted from the grain will be significantly lowered. (If the conversion temperature is between 150° and 158° F, the yield should be normal.)
The temperature of the sparge water should also be taken. If it is too hot (over 170° F), tannins will be leached out the grains, causing astringency. All brewers should monitor their fermentation temperature and keep it within its proper range. Usually, ales are fermented at 60° to 72° F, lagers at 45° to 55° F. To monitor fermentation temperatures, the brewer should use a thermometer that measures the temperature of the wort, not the ambient temperature of the surroundings. The wort in a carboy can be as much as 10° F higherthan ambient temperature at the peak of fermentation. Using a temperature strip similar to those used on aquariums is a great way to measure temperatures.
Brewers should test all their thermometers for accuracy. The easiest way to do this is to measure the temperature of boiling water and ice water. Boiling water should be 212° F (100° C) at sea level; ice water should be 32° F (0° C). Of course, some thermometers do not cover either of these ranges.
To calibrate a thermometer whose range doesn’t cross 32° F or 212° F, get a good-quality laboratory thermometer. Use the good thermometer to take the temperature of a liquid. Then, measure the temperature of the liquid with your other thermometers. If the readings don’t agree, add or subtract the amount of error when using your everyday thermometers. In addition, some electronic thermometers have calibration screws. Whenever taking thermometer readings, be sure to wait until the reading has stabilized before recording it. Few thermometers give instant measurements.
Brewing Notebook:
Without a notebook to record the results of tests and experiments, lab equipment is useless. Every brewer should keep a brewing notebook and record his recipes, procedure and tasting notes. It is more important to record how your brewing session actually went than to record the original plan for your brew. If the recipe is altered in any way — for example if you run out of one type of hops and substitute another — you should record this. If you goof up one of your procedures, you should record this as well. With this, you will be able to distinguish between inconsequential deviations in brewing procedures and errors that may cause serious problems.
Your detailed brew-day and fermentation notes should be complemented by extensive and focused tasting notes. It doesn’t make any sense to record your recipes and procedures if you don’t correlate them with the finished product. One of the simplest ways to ensure that you are taking complete tasting notes is to fill out a homebrew contest judging form for each of your beers. Most homebrew books have examples of contest forms. You can also download beer judging forms from the Beer Judge Certification Program website at www.bjcp.org. These forms have spaces for comments on appearance, smell and taste of your beer.
Although your impression of each isolated sensory element is important, it is also important to record your overall impression of the beer. Beers with easily detected faults are usually not very good; however, a beer without faults may still not be very good. Your overall impression is as important, perhaps more so, that your element-by-element analysis of your beer.
Lab Equipment for the Serious Brewer:
The equipment in this section is for serious brewers, especially those who are using all-grain techniques. Using these gadgets, a homebrewer can focus on consistently brewing good beer and also can troubleshoot a variety of common brewing problems that may arise.
Iodine and Test Plate:
The iodine test detects the presence of starch in a solution. The only equipment you need is a dropper full of iodine solution and a light-colored dish or test plate. To perform the iodine test, a brewer simply adds a drop of iodine solution to a small volume of wort. Usually the wort is on a light-colored plate or in a specialized test dish with multiple little reservoirs to hold liquid. (If you use a dinner plate, don’t use it for food after iodine has been on it. This is a bit paranoid, but it’s better to be safe than sorry.) If starch is present, the wort and iodine solution turns purple or black. If there is no starch, there is no color change. Note: It is very important to cool the wort sample before performing the test.
All-grain brewers use the iodine test to assess the success of their mash. If a mash was successful, all the starch in the grains will have been converted to sugar. The iodine test is done only once per brewing session, unless the test is positive. If the test is positive, the brewer should extend the time of the mash, or correct the mash temperature, until starch conversion is correct.
If an incomplete starch conversion is not detected and corrected, the resulting beer may suffer from starch haze. Many all-grain brewers use the iodine test when they first start mashing or try a new type of mashing like decoction mashing or a multi-step mash regime. After becoming more experienced at mashing, however, many quit doing the iodine test.
pH meter:
A pH meter measures how acidic or basic a solution is. Some meters are designed to sit on a benchtop, while others are hand-held meters. To measure pH, a small sample of the beer or wort is taken and cooled down. Some pH meters only give accurate readings at a single temp (often 60° F). Others automatically compensate for temperatures within a given range. Even with a temperature-compensating model, you should cool the wort down before taking a reading. The electrodes on pH meters burn out much faster if used at high temperatures. To save wear and tear on the electrode, cool down your wort before measuring pH.
To get the most out of your pH meter, you should keep your electrode clean and free from scratches. It should be stored in electrode storage solution. Whenever the pH meter is reading, the electrode should be immersed in liquid. And, before every reading, rinse the electrode in water and swirl it around in the solution to be tested for a few seconds before taking the reading.
There are many times during a brewing session when taking a pH measurement is valuable. The pH of the mash should be taken, to determine if it is in the optimal range (pH 5.2 to 5.4). If the pH is too high, it should be adjusted downward by adding acid or calcium sulfate. The pH of the final runnings can be taken; you should stop sparging before the pH exceeds 6.0 or you’ll risk extracting tannins.
The pH of the wort should also be taken. Wort pH should be 5.0 to 5.5. This can be adjusted with acid if it is too high. There is usually never a problem with wort pH if the mash pH was O.K. unless the brewing water is very hard. The pH of your finished beer should also be taken. Often, the pH of the final beer describes how “lively” a beer is. An otherwise well-brewed beer can taste lackluster if the pH is too high. And, high wort pH during boiling can cause a harsh hop bitterness. Most finished beers have a pH of 4.0 to 4.6.
To calibrate your pH meter, you will need two solutions of known pH. Buffers of pH 4, 7 and 10 are the most commonly used known solutions. Brewers should use pH 4 and pH 7 buffers to calibrate their pH meter. How exactly you calibrate the meter varies; the instructions to will tell you how to do this.
For all-grain brewers, a pH meter is very useful. This is especially true for all-grain brewers with hard water. When using hard water, the proper mash pH does not automatically establish itself. Therefore, pH adjustments must be made by adding acid or calcium sulfate (gypsum).
Kitchen Scale or Lab Balance:
There are a lot of different types of scales or balances available. Most hombrewers use a spring scale or an electronic kitchen scale. Some may own, or have access to, a laboratory balance. To measure weight on a scale, weigh the empty container your ingredients will go in. Then weigh the ingredients and the container. Subtract the weight of the container to get the weight of the ingredients.
To measure weight on a balance, place the container that will hold your ingredients in the pan and press “on” or “tare.” The balance should then read 0. Next, weigh out your ingredients; the scale will automatically subtract the weight of the container from the weight displayed on the screen.
If you have a scale, you can buy your brewing ingredients in bulk and weigh out as much as you need each time. You no longer need to rely on pre-weighed sacks of grain or hop additions from beer kits.
You should calibrate your scale using a known weight if at all possible. The scales available to homebrewers or cooks can be off as much as 20 percent.
Microscope & Hemacytometer:
A typical laboratory-quality microscope allows us to see objects up to 1000X smaller than we can see with the naked eye. This is powerful enough to see individual yeast cells. In fact, brewers can use a microscope to count yeast cells and bacteria in their wort or beer.
Counting yeast cells allows brewers to accurately determine their pitching rates. The optimal pitching rates are 1 million cells per milliliter per degree Plato (roughly four gravity points). In order to count yeast cells, a brewer must use a hemacytometer. A hemacytometer is a microscope slide that traps an exact amount of liquid under the cover slip. The slide itself is striated so that, when looking through the scope, the brewer sees a checkerboard arrangement. On top of each square of the checkerboard, a known volume of liquid is trapped. A small amount of liquid from the yeast starter is diluted and a drop is put on the hemacytometer. By counting the number of cells in one square, the brewer determines how many yeast cells are in the small volume above that square. The brewer can then calculate the concentration of yeast in his starter from the number of yeast cells in the square, the dilution factor of the sample, and the volume of liquid enclosed in the square.
With the proper staining, yeast health can also be ascertained with the use of a microscope. Dead cells stain blue, while living cells remain colorless. By counting the number of clear cells and the number of dead blue cells, the brewer can determine the number of healthy cells. Usually, brewers want over 95% of the cells to be healthy. Otherwise, initial fermentation can be sluggish and the dead yeast can taint the wort with off flavors.
The key to viewing yeast cells, or any opaque objects, with a microscope is to limit the amount of light shining through your sample. Most microscopes have a dimmer to the light source. Most also have a diaphragm under the stage you can open or close to adjust the light level. If you keep the light levels low you will easily be able to see the yeast cells. They are clearly visible using a 40X objective. (This actually equals a 400x magnification, because the eyepiece has a 10X magnification).
And in Conclusion…
For me, part of the fun of brewing is taking a bunch of readings and manipulating brewing variables to produce good beer. But I try not to forget that brewing gadgets are just tools to use when crafting a beer, not an end to themselves. Don’t let secondary measures of brewing success — like hitting the right pH — become your focus. Your palate will always be your most important brewing gadget.
Illustration by Don Martin
