Ask the Experts
Homebrew expert Brad Smith, author of the Beersmith homebrewing software and the voice behind the Beersmith podcast, tackles questions about ph meters, eliminating bacteria, and over carbonating a batch.
I purchased an inexpensive ph meter to manage my mash ph, but I’m having a hard time getting consistent readings from it? Managing your mash ph within the 5.2–5.6 range is important for all-grain brewers. While you can estimate mash ph and make basic adjustments using software, it is still important to have a good-quality ph meter to verify your ph.
You mention that you purchased an inexpensive ph meter, and this could certainly be the source of your problems. Many low-cost meters are not terribly accurate, having variability of +/– 0.1 ph or higher. Very cheap ones may not be suitable for beer brewing.
Some of the features you should look for in a ph meter include an accuracy of +/– 0.01 ph, automatic temperature compensation, a good (digital or analog) calibration system, and—ideally—removable probes. Removable probes let you replace the ph electrodes, as these will wear out and become non-linear within two to three years for a typical unit.
A second source of your problems could be improper calibration of the unit. Any ph meter must be calibrated before use. To do this, you need to purchase a “ph Buffer Calibration Kit.” The kit contains three different solutions with a known ph of 4.0, 7.0, and 10.0. In addition, I recommend purchasing electrode storage solution, which is a solution you want to store your probes in to extend their life and maintain calibration.
For a digital ph meter, you simply push the calibration button and then put the probes into each of the fixed solutions when prompted, and the unit will measure each and calibrate the unit. Calibrating an analog unit is similar, but typically you adjust a different calibration knob for each of the known solutions.
What I recommend is to calibrate your unit using the known solutions and then wait a few hours and measure the known solutions again. You should get good readings from the unit as it should be able to maintain calibration for at least a few days if you properly store your probes in the storage solution. If you don’t get good readings from the calibration buffers, I would consider replacing the meter with a good-quality ph meter with the features mentioned above. Your sour-beer problem is almost certainly being caused by bacteria. Bacteria such as Lactobacillus and Pediococcus occur naturally and will infect and rapidly sour a batch of beer if you don’t kill them off using sanitizers. These bacteria produce lactic acid and are widely used in sour-beer brewing.
Poor sanitation could be the cause, but if you have not changed your sanitation process in the past year, it may not be the problem. The fact that the problem is occurring from batch to batch and you did not have it earlier indicates that some of your equipment may be infected. Most likely one or more pieces of equipment on the “cold side” of your system are infected with bacteria, which is then souring your beer during transfer, fermentation, or storage.
I say that the “cold side” is the problem because your beer is not subject to infection during the mash, and the boil as the act of boiling will kill any bacteria. However, it is possible for your chiller, pump, transfer tubes, fermentor, or even bottling bucket or kegs to be infected.
The most likely location for an infection is plastic, rubber, or silicone. Unfortunately, even a small scratch in a plastic bucket can harbor bacteria that are very difficult to remove. While stainless-steel and other metals are largely impervious to infection if properly sanitized, it is possible for your fittings, gaskets, valves, pump heads, and tubes to harbor bacteria.
At a minimum, I recommend disassembling all of your fittings, hoses, gaskets, valves, pump heads, and other interfaces
Last year I was making some great beer, but several batches ago I started getting sour flavors in my beer, and it seems to be getting worse with every batch. What can I do?
and giving them a thorough cleaning and then soaking for a bit in sanitizer. If that fails, you might want to consider replacing old hoses, gaskets, plastic utensils, and other rubber and plastic in your system to eliminate potential sources of an infection.
Finally, I want to mention that it is also possible to create sour beer if you have improperly stored ingredients, such as wet malts. In this case, an infection of the malt before brewing can produce lactic acid in the malt or mash that then can carry forward to the beer. Essentially, you are creating a sour mash. This is far less common than a cold-side bacterial infection, but it is a possibility you should be aware of.
I’ve recently started brewing with extract and my beers have been consistently overcarbonated. What could be the cause?
There are several possibilities, including too much carbonating sugar, bottling too soon, and using poor-quality malt or yeast. Let’s walk through each of these one at a time.
First, it is possible you are using too much sugar to carbonate the beer. For example, a lot of beer kits come with a generic amount of corn sugar (or other sugar) to be used for carbonation. It’s not uncommon to see a package of 5 oz (142 g) or more of corn sugar. However, to achieve an average level of carbonation on a 5 gal (19 l) batch, you really only need about 4.2 oz (119 g) of corn sugar.
You can also run into similar problems if you try to measure carbonation sugars by volume. Old books often had things such as “2/3 cup of corn sugar” to carbonate. Not surprisingly, corn-sugar density varies depending on source, so 2/3 of a cup could be too much or too little.
To avoid both of these issues, I recommend you calculate the proper weight of sugar needed using software or an online calculator and then weigh the corn sugar (or other sugar) to get an exact amount.
Another possibility is that you simply bottled your beer too soon. When you do this, the beer will continue to ferment in the bottle, over carbonating your beer. Many new brewers are quick to bottle their beer so they can enjoy it. More experienced brewers are a little more patient. Don’t rush to bottle your beer just because the bubbler on the airlock stopped bubbling.
Use a hydrometer and make sure you have a stable finishing gravity for at least a few days. If you can, give it another week after you think fermentation is done. This will give you some extra insurance to make sure fermentation is done before bottling and also aid in developing clarity in your beer.
Finally, it is possible that the quality of your ingredients led to over-carbonated beer. Low quality or older malt extract, for instance, can often ferment and finish much more slowly than fresh malt extract, again leading to continued fermentation in the bottle. The same can happen if you use poor-quality yeast or an insufficient quantity of yeast. So whenever possible, only brew with highquality fresh malt extract and a sufficient quantity of fresh yeast.