Starting a Brewery Lab 🔬🍺👩🔬
Nerding the F Out is meant to cover all kinds of topics; not just video games. While there will be plenty of talk about my adventures smashing the A button, this is about another passion and how I spend some of my work week. This topic is a result of the internet failing in providing me with something for the scale I work at. What’s that scale, you ask? Well, I have the corner of the only office in the brewery. I don’t have: much counter space or storage, a sink, proper outlets, or privacy. This room houses the desks of three other employees, the main printer, and occasionally a dog. I’m fortunate that I’ll be assisting in planning the future lab space in the building we are expanding into. Exploring the process of planning a lab will be a future post.
I’ve now gone to several workshops and classes, poured over webinars, and have been running my own quality control lab for a year. I also just filled an entire composition notebook, so yeah, I’d say I’m pretty qualified. Here’s my attempt to guide those that might want to follow in my footsteps… or at least learn from my pitfalls… OR for those that might be curious what it is I do when I’m not killing myself stirring mash or lugging kegs.
I’m going to present this topic in likely two posts, maybe three. This week’s post focuses on the microbiology component of my lil’ lab. I realize there might be some words that don’t really have a good layman’s equivalent. I’ve done my best to define them in the post and at the end of the post (italicized words).
During my time initially exploring Quality Assurance/Quality Control (QA/QC), I only focused on microbiology. Admittedly, this was hard to avoid as the class and workshops I went to all focused almost exclusively on yeast, plating, etc. Yeast is without a doubt the workhorse in the brewhouse and when you’re harvesting and re-pitching that yeast for several generations, you want to ensure you’re not perpetuating a problem. So, that’s where my lab got its start. The mission: Go/No-Go on yeast.
A QA/QC program has always existed at the brewery. Daily samples are taken from fermenters with actively fermenting beer for gravity and pH readings. Those samples are also smelled and tasted to ensure there’s no off flavors or aromas present. Additionally, diligent cleaning processes are followed, quality ingredients are used, yeast cell counts are done when needed, etc. However, these are all processes that are done on a macro scale (well, with the cell count being kind of an exception as it is a process requiring microscopy) and can be confirmed with human senses.
We already had a microscope and hemocytometer in house, but that was it. The first toys I got to purchase were a fridge, an incubator, and a small butane burner. (I’ve also purchased a titration set-up [burette, stir plate, etc.] since.) This brings my total toy count to: microscope, fridge, incubator, and a flame source to work near. I can argue these pieces of equipment are the very bare minimum of a small brewery’s micro lab. An autoclave would be great, but to work around an inability to sterilize, we use pre-made beer-spoiler selective media.
Okay, what is “pre-made beer-spoiler selective media”. Basically, a lab has created a media that, in this particular case, will change color (red to yellow) if it detects a micro-organism known to spoil beer. I use pre-made test tubes with a broth version of the media and I create plates (petri dishes filled with media) by liquefying agar delivered in sealed glass bottles. I actually use a sous vide we have in the brewery as a water bath to liquefy the agar. A water bath might be necessary if you want to use this particular media and want it to melt in a reasonable amount of time.
For the test tubes, I place a sterile swab in a sample and then snap the swab off inside the tube. For the agar plates, I place a sterile inoculation loop in a sample and streak it on the surface of the agar. I clean my work bench with Lysol wipes before I begin to work. Placing a sample in/on media is done under an open flame, which creates a clean area to work within. The heated air next to the flame creates an updraft removing potential contamination in that space. The use of a flame isn’t necessary if you have a laminar flow cabinet/hood (clean air is blown at the user) to work in/under. While careful aseptic techniques can be used all day at your work bench, if your sample is compromised during collection it’s all for naught.
I first started collecting samples in small plastic bags called Whirl-Paks (you spin, or whirl, them shut after you collect your sample). These gave me problems right away. I purchased bags that were too small to carefully collect the stream of beer from the sample port and they were impossible to prop up when I would go back to the work bench. While they are easier/more space-saving to store because they’re flat, they weren’t working. I switched to sterile 4oz plastic vials with snap lids and haven’t looked back. I sanitize the outside of the vials with peracetic acid before collecting the sample. We chose to not flame the sample valves, so to ensure a clean sample collection, I put a freshly cleaned (caustic soak followed by a peracetic soak) sample valve on a freshly cleaned sample port each time I need to take a sample. It’s time consuming and I’m working on making this more efficient or potentially finding a way to eliminate it altogether. Before opening up the sample valve to let the liquid pour through, I spray the surrounding area and into the valve with isopropyl alcohol. Overkill? Possibly.
I collect samples within 24 hours after wort has been inoculated with yeast and after the beer has been moved (dry-hopping, recirculation, transferring, filtering, etc. Basically, whenever there’s a chance for contamination to be introduced). Samples collected later in the beer’s life cycle are used to check on processes and ensure that the product going to customers is without problem. All collected samples are put into the broth test tubes. Samples from the Brite tank (packaging tank) or from kegs/cans/bottles are put on three agar plates per sample. Test tubes and plates with samples in/on them go into the incubator.
WOO That was a marathon. Here's the round up if you started to drift off. Lemme know if you have questions and if there's something you wish I had expanded on. Could be a future post. Cheers
Brewery micro lab sans autoclave
- Fridge (storage of samples, media, poured plates, etc)
- Flame source (or laminar flow cabinet if ya fancy)
- Lysol wipes
- Isopropyl alcohol
- Sterile petri dishes
- Inoculation loop (platinum can be re-used, disposable should be sterilized before use and then chucked)
- Sterile swabs
- Pre-made media (I use NBB by Döhler)
- Sterile sample vials
Sample whenever the beer moves
Harvesting (yeast): To collect healthy yeast from a fermenter with the intent of re-using the yeast.
Pitching (yeast): Injecting yeast into a fermenter along with the wort it will ferment.
Gravity: A reading using an instrument called a hydrometer to determine the density in a liquid. In a brewery’s case, this is to determine the amount of sugar in a liquid. Gravity is way for brewers to monitor the progress of a batch of beer. Initially a high gravity (aka sugar-rich) wort (sugary grain juice) is added to a fermenter with yeast. Yeast eat the sugar, creating CO2 and ethanol (and flavor compounds), to create beer from wort. The gravity (sugar density) will decrease as the yeast does its job.
Microscopy: using a microscope, basically
Hemocytometer: made for use with blood, hence the “hemo”, a microscope slide that contains a laser engraved grid used for counting cells. The volume of the slide chamber is known and it is used to extrapolate the number of cells in a given volume. This is useful for determining yeast health in a brewery.
Media: a liquid (broth) or jelly-like (agar) substance that encourages the growth of microorganisms
Aseptic technique: working in a sterile manner to avoid contamination
Peracetic acid: an acid used to sanitize; you can’t sanitize what’s not clean
Caustic: a strong base used to clean