Microbial Testing in Beer

When you open a beer, you expect it to be clean, fresh, and exactly how the brewer intended. But sometimes, unwanted microbes sneak into the process and even small amounts can ruin flavor, cause haze, or spoil shelf life.

At our laboratory, we offer microbiological testing and identification to help brewers catch contamination before it becomes a bigger problem. One of the most powerful tools we use is Raka Ray agar a selective medium that helps us find beer-spoilage bacteria fast and accurately.

Why Microbial Testing Matters

Microbial contamination can cause:

Issue	Caused By
Off-flavors (butter, vinegar, medicine)	Wild yeasts, Lactobacillus, Pediococcus
Overcarbonation / gushers	Diastatic yeasts or bacteria producing CO₂
Haze and sediment	Bacterial growth post-packaging
Shortened shelf life	Live contamination continuing in bottle or keg
Stuck fermentation	Wild microbes interfering with your yeast

Even in clean breweries, contamination can come from:

Packaging lines
Poor tank sanitation
Hops, fruits, or barrels
Infected yeast pitches
Faulty seals or valves

What Is Raka Ray Agar?

Raka Ray (RR) agar is a special type of growth medium designed to detect and isolate anaerobic and facultative anaerobic beer-spoilage bacteria, especially Lactobacillus and Pediococcus, two of the most common culprits in contaminated beers.

Why we use it:

Selective for beer-spoiling organisms
Low pH and hop compounds simulate beer conditions
Inhibits most non-relevant microbes (e.g., molds)
Shows distinctive colony growth to aid identification

It’s a proven method, recommended in MEBAK and other brewing microbiology guidelines.

What We Test For Using Raka Ray

We use Raka Ray to detect bacteria such as:

Lactobacillus brevis
Pediococcus damnosus
Other anaerobic/hop-tolerant spoilage species

Our lab can:

Isolate colonies
Incubate under brewing-relevant conditions
Identify morphology

This allows you to know not just if there’s contamination but what kind, and how to respond.

When to Consider Microbial Testing

You should test for microbial presence as Part of production routine and if:

Your beer develops unexpected off-flavors (buttery, sour, medicinal)
You notice overcarbonation, haze, or secondary fermentation in package
You’re doing contract brewing and need peace of mind
You plan to export or store beer for extended periods
You’re pitching harvested yeast or reusing cultures
You’re experimenting with non-pasteurized or barrel-aged beers

Testing is especially recommended after:

Packaging line issues
Cleaning failures
Sour/funky flavors in otherwise clean styles
Dry hopping or fruit additions

What You Get from Our Microbial Test

At our laboratory, we offer microbial testing using Raka Ray agar (and other media) that includes:

Sample incubation under controlled conditions
Visual inspection and colony isolation
Identification of spoilage bacteria
Feedback and interpretation: is this a real risk or just background noise?
Recommendations for cleaning, yeast handling, or rebrewing

Turnaround time: typically 5–7 days after sample reception.

Final Thoughts

You can’t always see contamination but you’ll definitely taste it later.
With Raka Ray agar and expert microbial analysis, we help you catch issues early and keep your beer clean, shelf-stable, and exactly as you intended.

Send us your sample, and we’ll help you keep the good bugs in and the bad ones out.