Real-time fermentation monitoringPerhaps now more than ever, you’re forced to do more with less at your brewery. With money likely tight and a staff that’s probably stretched thinner than usual, we’re all seeking to  maximize efficiency, productivity, cost savings and time.

BrewMonitor is the industry’s first real-time, comprehensive fermentation monitoring and analysis solution, purpose-built to enable brewers to increase quality and profitability through greatly enhanced fermentation-process control. To show exactly how real-time fermentation monitoring helps make better beer, reduces workloads, and minimizes stress, we’re publishing a series of blog posts to walk you through what it can do for you at each step of fermentation.

This is the second article of three (read Part 1). We’ll post another installment within a few weeks. Keep monitoring this space!


Most brewers don’t know whether their fermentation has taken off until they come in the next morning and check for activity in the blow-off bucket. Instead, BrewMonitor can let you know immediately if everything’s on-track by alerting you when dissolved oxygen hits zero, pH gets down to 4.5 and gravity drops by 1°P.

To take extra care, you can check the data for human error on your phone two-to-six hours after the pitch. This way, if your readings are out-of-range, you can troubleshoot to determine whether, for example, the blowoff valve was opened and the chiller was turned on.


By day 1, you should see some movement in gravity, depending on the style of beer. Most ale fermentation will have dropped, though it’s normal for some lager strains to not have begun fermentation yet. If the gravity of your ale hasn’t moved at all, check the other indicators of yeast activity.

Dissolved Oxygen (DO)

The oxygen should have been consumed by the yeast at this point, with the possible exception of lager fermentations. The DO should drop below the threshold of the sensor range (1 ppm) and remain there for the rest of the fermentation. If it takes more than approximately 12 hours for DO to drop, you have an indication that you or your brewer may have underpitched the yeast or that yeast health is otherwise compromised. The exact timing, of course, depends on your strain.

If this happens, pull some samples to check your cell counts and health. Do you need to add more yeast? If you were planning to repitch this yeast, it may be time to start planning alternative sources to prevent compromising future batches.


We typically see a rapid pH drop, falling around 0.5-1.5 pH in about a day, dependent on style and yeast activity. If the pH hasn’t dropped past 4.5 and DO is still present, you risk growing enteric and other pH-sensitive bacteria. The earlier you know this, the earlier you can rectify by adding more yeast and the lower the chance you’ll have to dump the batch.


To keep the yeast healthy and promote brewery safety, check the pressure reading or set an alert for a reading that exceeds 10 PSI. A number that’s too high could indicate the blowoff valve is closed or blocked. Excess pressure will increase dissolved CO2 levels and can become toxic when it combines with increased pressure on the cells. If you rely on the pressure release valve to vent it will likely react too late to save the yeast.


The fluid temperature should remain constant depending on the cooling jacket settings. Use the alert function to inform you when to make any scheduled temperature changes or for temperatures that go 39°F over or under target to let you know right away that you have a cooling problem potentially created by chiller trouble or a stuck solenoid.


When fermentation kicks off, the generation of CO2 in the wort will cause the conductivity reading to drop slightly. This is not a change in the conductivity of the wort, simply an indicator of CO2 production and therefore a confirmation that fermentation is underway.

If fermentation goes off-track you don’t have to wait until too late to do something. You can rescue a batch or plan for how to deal with it long before you might have otherwise. You may lose a batch or know you won’t have yeast to repitch but you can save days of wasted time by being forewarned.

Check back for the final installment, where we’ll discuss Day 2 through the end of fermentation.

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