BSI: Brew Scene Investigation
The first thing I noticed was the musty smell, like a locker room. We had been called to a residence early on a Sunday morning where the owner, a Mr. Crossley, had apparently received the shock of his life. He had immediately called us — not merely because we were the best, but because a guy like him doesn’t have many options. If he had been thinking clearly, he probably wouldn’t have called us at all, and saved himself a world of hurt. But he had panicked, and now we were there.
A single flickering shoplight lit the garage. Looking around, I could see a bunch of stacked cardboard boxes mostly blocking the single window, some firewood, a workbench and a kegerator. The workbench was against the wall and had a propane burner, pot, a cylindrical beverage cooler and various other items stacked on it. I realized I was looking at a makeshift brewery.
The subject was in the back corner of the garage, by the workbench, and next to some plastic bins marked “2-Row.” I was appalled; what was it doing here? I couldn’t see any movement at first, but then I heard a faint click and saw a bubble move in the neck — definitely still alive. But why was it here? The garage was warm, even on a Sunday morning it was easily 75 °F. I bent down and sniffed cautiously. Besides the musty smell that pervaded the garage, I could smell the faint sweet odor of vinegar.
“Is this the one you called us about?,” I asked.
“Yeah, It’s a sweet stout. I just took it out this morning to keg it and it seems to have started fermenting again.” I glanced at my partner, Steve, to see if he was ready. He nodded. Crossley stood to the side, apparently afraid to watch. I sighed, reached down and lifted the lid. “Dear God!,” my partner gasped, “That’s sick!”
Nodding, I looked closer and felt a chill go down my spine. The surface of the fermentation looked like kräusen, with white patches dotting the surface. But it was too shiny and wet, like something out of the “Alien” movies. This was definitely not a normal fermentation. It looked like bubbles were building up under a gelatinous layer covering most of the surface. This beer was definitely sick. I waved my hand over the fermenter, drawing the odors toward my nose. The beer smelled sick too: sweet, buttered popcorn, vinegar and plastic.
I looked up at Crossley and said, “When did this happen?”
“I dunno, last night I guess. It was fine yesterday.” His story didn’t make sense, beer contaminations take weeks to develop to this stage. He looked nervous.
“When did you brew this?,” I asked.
“A couple weeks ago.”
“Why is it sitting out here instead of in the fridge?”
“Like I said, I was going to rack it to a keg today.”
“Has this ever happened before?”
“N-n-no! I mean, why would it? I keep the place clean, ask anyone! Maybe someone else was in here, climbed in through the window or something . . . ” He started looking panicky.
I held up my hand to forestall any more explanations. “Do you have a sanitized spoon?”
“Uh, sure, sure, I’ll be right back.” He headed for the kitchen.
There were signs of spillage down the sides of the bucket, and stains on the floor, but there was no condensation and the bucket was warm. The odor seemed to come from the stains too. I stood up and gestured to Steve to have a look. “What do you think?”
Steve took a couple of cautious sniffs and then pulled out a flashlight to get a better look. He looked at it for a few seconds, then asked, “Acetobacter?”
“Possibly,” I said, “it smells like it, but that pellicle is thick and white enough that it’s probably Brettanomyces. An Acetobacter pellicle is thinner, more like a film.”
Steve looked back in the bucket and said, “There’s bubbles under the pellicle.”
“Yeah, I noticed that,” I said. “That’s another reason I suspect Brett, since it produces CO2 and Acetobacter doesn’t produce much at all.”
Steve nodded, then said, “It could be Lactobacillus though, that would explain the vinegar smell and the CO2.”
“True, but Brett will also produce acid if there is oxygen present . . . Do you smell anything else?”
“I’m not sure, it’s just so funky . . .”
“Yeah, we’ll know more in a minute.”
Crossley came back with the spoon. I handed it to Steve.
He poked the spoon through the pellicle to get a sample of beer. “It’s ropy,” he said. Gelatinous strands hung briefly from the spoon before falling back into the beer. “Yeah, I’m not surprised,” I said.
“That ropiness or ‘sickness’ is a sign of a Pediococcus infection. What do you taste?” He sighed, muttered something about illegitimacy, took a sip, and made a face. “Ugh, Phenolic,” he said, wincing. “Diacetyl and phenolic.”
“Yep, a strong phenolic character is another characteristic of a young Brett infection. It will be reduced to some extent as it ages, but mostly it will merge with the typical leathery, barnyard character that Brettanomyces fermentations are known for.”
I pulled a notepad and pencil from my pocket, thought a moment, and filled in a square on a Sudoku puzzle I’d been working on. “Did you oak this beer Crossley?”
“No.”
“Hmmm, maybe it came from the woodpile . . .” Brettanomyces is not that easy to catch. Pediococcus is. It’s everywhere and most restaurants that don’t clean their keg lines regularly have Pedio infections in them. Lactobacillus is fairly common too, but Brettanomyces is associated with wood, although once it gets into your equipment it is very hard to get rid of, and will often contaminate subsequent batches.
Steve attempted to hand me the spoon, but I turned toward the kegerator. The diacetyl most likely meant Pediococcus, and if Crossley had Pediococcus in his fermenter, then it was probably in the concrete floor and throughout the brewery. I was betting it was in the kegerator too. Pediococcus also produces lactic acid, but it does it without producing CO2, like Lactobacillus and Brettanomyces do. It tends to be a more sour character, than either Lacto or Brett, too.
The kegerator had a single tap coming out of it, and the drip tray was stained with old beer. Inside were a couple of empty six packs and two Corney kegs. One was connected to the faucet, the other had a cobra picnic tap on it. I shook them. The keg that was online was nearly empty but the other was about half full. Both wer cold, at serving temp, not fermentation. I could see where beer had spilled around the liquid-out poppet, and there were more beer stains on the walls. It smelled musty too.
“What are these?” I asked Crossley.
“That’s my pale ale on tap,” he said, “and a double IPA in the other keg.”
Time to test my hunch. I took a collapsible plastic cup from my pocket, and drew a pint from the cobra tap. Sniffed it; strong herbal hop aroma, alcohol. Tasted it; hoppy, bitter, clean, not bad, not bad at all . . . I knocked the rest of it back and poured a pint from the faucet. There was a burp, and a small green chunk of something was floating in my cup. A hop? . . . I didn’t think so. I raised the cup to my lips but didn’t drink it. It smelled like old butter and leather. Pedio and Brett again. I opened the side door and tossed the swill outside. Strange, one good and one bad. Why not have the good one on tap? “Do you drink your own beer regularly Crossley?”
“Yeah, everyday, mostly, why wouldn’t I?”
“You tell me. When was the last time you drank from this?”
Crossley grunted and looked at floor. “I’ve been working a lot. I have a regular job now . . . But my roommates drink my beer all the time.”
“Really, do you have many roommates?” I didn’t wait for an answer as I gestured for Steve to look outside.
A minute later Steve was back with a grin on his face. “Barrels of empty bottles, Chief.” I raised an eyebrow, but he shook his head and said, “No, all micros.”
“Recent?”
“Some, yeah.”
My turn to grunt — those fast food burritos just don’t sit well.
I turned back towards the bucket. “How is the acidity?,” I asked Steve. “Is it sharp like vinegar or just sour and tart?”
“Hmmm, just tart. Here, I’ll get you some.”
“No, that’s okay. Close it up.”
Let’s see, I thought, definitely Pediococcus and Brettanomyces, probably not Acetobacter from the sound of it. No sign of fruit flies or bees in here, although there had been a dead squirrel by the front door. Where were these contaminations coming from? That was the question. There was the woodpile and the dirty concrete floor . . . Looking around, I noticed a bottle of iodophor sitting on the edge of the workbench. I took a closer look at the sanitizer in the airlock; it looked fresh. A-ha! I bet it had run dry and he had just refilled it this morning before we arrived. I turned to ask Crossley about this, but at that moment the kitchen door opened and Charlie looked in.
“Chief? You gotta see this . . .” He had hung back to check out the rest of the house while Crossley led Steve and I to the scene of the crime. I thought he meant the bottle of Lagunitas Maximus he was drinking from, but he beckoned us back inside and led us to the living room.
A large jacketed stainless steel fermenter stood in the middle of the room with an extension cord connecting it to the wall socket. It was the self-cooling type, a 12-gallon technical marvel that seemed grossly out of place here.
“A-ha! Care to explain this?! Are you two-timing now?”
“It’s not mine!,” he interjected, “We just borrowed it, I mean, my roommate borrowed it . . .,” he mumbled.
Borrowed, riiiight . . . Smirking, I started to reach for the lid, but Charlie stopped me. “I tasted it, Chief, it’s clean.” Hmmm, maybe it wasn’t his after all. And it did explain that other keg . . . I let my hand drop and turned back to Crossley, fixing him with a steely glare.
“Alright Crossley, I’ll take your word for it, but I want to know what you were doing out there in the garage.”
“I was getting more dogfood, and just happened to see it . . .”
“Not today, dammit, last week, last month! I want to know what you thought you were doing when you brewed that poor bastard! That’s supposed to be a sweet stout, but it’s not so sweet anymore, is it! The kegs are cold, but the fermenter is warm — and the airlock looks recently filled! What’s up with that!?”
He sagged down onto the couch and looked at the ceiling. “It was my own recipe, I was going to surprise the other guys in the club, you know? Blow their minds with a really outstanding batch. It was going so well . . .”
“Did you have it in the fridge?,” Steve asked.
“Yeah. I . . .”
“Why did you take it out?,” Charlie asked gently.
“I had it in there for about a week at 65 °F (18 °C), and it seemed like it was done. We were having a party, so I took it out and put the Cornies back in.”
“When was this?”
“Last, uhhh, okay maybe a couple weeks ago. I don’t remember . . .”
“Hold on,” I said, “Start at the beginning. What was your recipe?” He told me and it sounded good, like something I might make. “How did you brew it?”
“It was a single temperature infusion mash in a 10-gallon (38-L) Gott cooler. Batch sparge, one hour boil.”
“Did you boil it in the garage?”
“Yeah.”
“How’d you chill it?”
“Immersion chiller”
“Any chance your chiller was leaking?”
“I dunno, why?”
“Because if you are using your garden hose, there is probably bacteria in there that can get into the wort. You should use dedicated hoses for chilling, preferably the white potable water hoses that are used for RVs — just in case.”
“How about your fermenter? Did you clean it well after the previous batch?”
“Yes, I scrubbed it out and soaked it with iodophor.”
“What was the previous batch? How did it turn out?”
“It was a Belgian Tripel, but I had to dump it . . .”
“Did you use a starter?”
“Yeah”
“What did you use for sanitizer?”
“Uh, iodophor”
“Do you crush your grain in the garage?” asked Charlie.
“No, I crush it outside to avoid Lactobacillus contamination. Hey look, I asked you guys here to help me fix my beer, I didn’t expect the Spanish Inquisition!”
I laughed derisively, explaining “Nobody ever does. Okay Crossley, here’s how I see it. You talk a good game but you’re a slacker. Your brewery is contaminated with Brettanomyces and Pediococcus; you have Pediococcus growing in your kegerator and you wonder why the batch went bad! This is two in a row! Constant vigilance!” I said, smacking my hands together for emphasis.
“So what now, what do I have to do?” he whined.
“I’m going to give it to you straight Crossley, you’ve got a lot of cleaning to do — every glass and stainless vessel in your brewery needs to be cleaned ’til it shines, understand? Scratched plastic and soft stuff like tubing has got to go. Sanitize everything, preferably with a different sanitizer than the one you’ve been using — it never hurts to keep the “bugs” on their toes. And finally, you gotta clean every stain, spot or spill in your fridge, on your floor or at your workbench; all of them are just reservoirs for contaminants.”
“What about the sweet stout?”
“Weeeeell, you’re lucky Crossley, at one time we would have said there was no hope for this batch either, but these days, we put you on probation, and let it sit for a few months. It may improve with age. You may even be able to drink it someday. Or, you may be able to blend it with another beer and make a good sour beer. Meanwhile, case closed.”
