The quality control of beer is one of the pillars of the quality management in the brewery. First the quality requirements of the beer as the final product of the brewing process are defined and concisely described as we shown previous articles hence the next step is to develop the beer quality control. The quality controls are performed over parameters that have a direct impact in one or several quality requirements.
The definition of a quality control should include the following items:
- Parameter to control
- Metrics and Units of measurement
- Description of the method and tools to be used to perform the measurement.
- Max and min values accepted for that parameter
- Corrective actions to be performed in case the value is out of the accepted values.
The requirements fall into three different groups in the brewery: raw ingredients or materials, technology and equipment and finally the brewing processes.
Quality Controls over raw ingredients:
- Parameters and specifications given by the providers.
- Be able to understand the specifications of the malt, hops and yeast in order to identify potential impacts on recipe due to change of specs. Be able to adjust recipe if needed.
- Analyze water characteristics and verify them weekly.
- Check viability of yeast if it’s reused before re-pitching.
These are just simple examples. The conclusion is that by keeping records of these parameters related to raw ingredients brewers can identify proactively a deviation before brewing a batch and then take actions, adjusting a recipe, changing the equipment, timers, etc to ensure the consistency of the final product from the first stage of the process, the ingredients.
Quality Controls over the brewing processes: brewers must identify the significant parameters for each stage and keep records of all of them in a process spreadsheet separated by tabs, milling – mashing – filtering – boiling – whirlpool – cooler – fermentation – maturation – …
- any other parameter of importance for each step
By keeping records of the parameters on real time the brewer can take proactive actions or even corrections before a variable is out of control and before it impacts in the process. Note that a single parameter like pH can impact in mashing, then decrease the yield extract, the performance of the batch, the fermentability and then alcohol. So we must consider the direct relationship between analytical analysis.
Once the analytical parameters are under control during the brewing process, it’s important to define quality controls in the final beer.
Quality Controls of Beer: again, we need to define a list of parameters that brewers can measure to guarantee that the final quality requirements are met and the beer has been brewed consistently batch after batch.
- Alcohol %vol
In summary the microbiologic controls of beer, there are different techniques to guarantee the beer doesn’t contain bacteria contamination that might produce off-flavors and reduce the life of the product in optimal conditions. There are different techniques but it’s frequent to use plates with specific media to detect bacteria, non-saccharomyces yeast, wild yeast, …
We’ve highlighted the importance of keeping records of the most significant parameters in raw ingredients, brewing processes and final beer. The goal is to post-process the data. By means of simple spreadsheets and graphics or more powerful tools we can check visually the comparison between batches and check if values are inside area of control.
With simple tools like a spreadsheet, it’s possible to draw control diagrams and check if a value is under control or a trend indicates that the brewer should take proactive actions to correct it. It’s possible to analyze the correlation between different variables, like ph-bitterness, mashing time-alcohol, etc.
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