New pH-meter, stability test

During these years we’ve been homebrewing I have always thought that it is better to walk step by step. Following this philosophy, a few weeks ago I decided to give another step forward within this hobby, seeking to control water used for brewing and mash pH. Until now, for all the batches brewed, we haven´t paid too much attention – if any– to either of these parameters. Beers brewed this way have been quite tasty, but I think this could be an important aspect of the process, one that could allow us to improve in the future, as some other homebrewers have already done (special mention to the Brulosophy blog and their exBEERiments about water chemistry) and bibliography references seem to remark.

To do this, first of all I should get a pH-meter. As each time I face a new purchase to improve/upgrade our equipment, my idea was to look for a reliable and long lasting model, if possible. I’ve never liked to buy bargains that break down easily, so as long as it weren’t excessively expensive, I didn’t want something of a questionable quality to save a few euros. First thing I did was to look for some information about the specifications that a pH-meter used for brewing should meet. After searching the web, I came across this post on Homebrewtalk, with a revised guide to by a pH-meter that convinced me. That post is based in the specifications that appear in the book Water: A Comprehensive Guide for Brewers, written by John Palmer and Colin Kaminski. These specifications are the following:

  •     +/- 0.02 pH accuracy
  •     ATC (Auto Temperature Control)
  •     Two-point calibration
  •     Sealed or refillable electrode with a resolution of +/- 0.02 pH or smaller
  •     Double junction electrode
  •     Flushable junctions, which allows for easier cleaning and longer life

You can check the details for these specifications (and more) in that post, and you can also read about some model choices that meet them. After evaluating prices and availability, I decided to purchase a PHH-7011 from Omega. It comes with a practical case with batteries, instructions, two buffer solutions for calibration (pH 4 and pH 7) and a little bottle with a solution for storage. I also purchased a replacement for the electrode.

Omega PHH-7011 pH-meter case

At first sight everything looks nice and, after reading the instructions, it doesn’t seem too difficult to use. Display visibility is very good and the electrode comes well protected with a screw cap. So far, truth be told, looks very good. Time for checking its performance. I planned a stability test for the pH-meter, something recommended in this other post, again from Homebrewtalk forums.

Omega PHH-7011 pH-meter

In this stability test, after doing the corresponding calibration of the pH-meter following the instructions, you must take readings of a pH 4 buffer solution for a period of time, at room temperature. These readings must be taken over time every couple of minutes up to about 20 minutes and then every 10 minutes or so for a couple of hours or more. Of course, this is not the funniest thing to do, but you can do other things between readings. After getting everything ready, I performed the test.

pH-meter stability test

Following the recommendations, I took readings every couple of minutes up to 20 minutes and then every 10 minutes up to 3 hours (you better find something to do between readings if you don’t want to get bored). With all the readings taken, I plot them on a graph. As you can see in the graph below, repeatability and precision were very good.

pH-meter stability test results

In view of these results, for now I’m very happy with my purchase and I’m looking forward to use it when brewing the next batches. From now on, when planning recipes for our brews we will have to take into account water related issues. Everything we can do to brew better beers each day.

*This post was first published in Spanish on 14 January, 2017

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