The Sour Mead: The Desolation of Lacto

…As recounted by the Alchemist

It’s a lovely morning at the Mead hall and the drums of honey are hot. The heating bands have been on them since yesterday, turning the older crystalized honey into a sticky soup of piping hot honey that will run through my pump. It was the first time putting a batch of this honey into the new 30 bbl tanks I had commissioned, and I was excited to see how they performed.  We had finally said goodbye to our trusty 15 bbl tank and replaced it with two 30 bbl tanks as we ventured into new territory.

It was uneventful, which was exactly what I was hoping for. This batch really needed to be perfect or we were not going to be able to meet our orders, next month. The tanks were sanitized per our established procedures and rituals. In all this time, the honey has never been a source of infection, due to its antimicrobial nature.  Everything was going along as usual, except now the batch was twice our usual size.

Once the batch was fully mixed and the yeast pitched, I left it to begin its magical transformation. Little did I know that deep in the dark confines of that stainless steel vessel more than just yeast was multiplying and consuming nutrients. A strain of Lactobacillus had come along for the ride and now found itself in a most hospitable environment.

The Lacto didn’t announce its presence for several weeks into fermentation when its souring waste products began to make their presence known to my tastes and alert me to this malfeasance present in my brew. By this point it was too late to affect the outcome and now I had a problem on my hands.

“How can I get rid of this robust bacteria feeding on my mead?”

I didn’t have the ability to deal with the problem directly, as the typical course to handle such a problem would be to hold the batch above 180F for several hours to kill off the heat-resistant intruders. I do not have a brew house or any other means to heat 1,000 gallons of any liquid to that temperature, so I had to turn to more creative means.

I had 2 problems to solve: First, I had to figure out a way to kill the microscopic gremlins currently present in our mead.  Second, I needed to find the root cause of the problem. Where did these interlopers come from? How can I ensure this event does not repeat? At least not unexpectedly.  

Honey is anti-microbial so, of course, that couldn’t be the source. Not only that, I heated the honey so I didn’t consider it likely that it was the provider of our microscopic hitchhikers. Was it the new (to me) tanks? The previous owner had mentioned they made sours, so perhaps we just didn’t do a good enough job scrubbing the tanks? Perhaps this would be the source of our infection. There was also some concern about the city water supply, as they had just had to do work on the water main supplying our building. Could this be the source of our woes? 

Armed with this knowledge we scrubbed the hell out of the tank and even hooked up a steam system to sanitize the tank. We upgraded our water filtration system and put it in service. Then, armed with new resources, I heated up another batch of honey and mixed it into the wort of a new batch.

That is when bad went to worse.

Not only did the sour happen again, it happened faster causing the entire ferment to accelerate. Now we have 2,000 gallons of sour mead and no reasonable explanation for why. So, having excluded all reasonable sources I had to consider the “unreasonable” idea that the honey, even heated, could have been the source of the infection.  

We needed to test the honey, so we reached out to our friends at Scofflaw Brewing who graciously agreed to help us out. We brought them samples of the honey which they tested in their lab. Sure enough, they found the infection and identified our unexpected guest. It was lactobacillus. We found the problem; now how do we fix it?

Like we always do: With Science and Creativity!  We had been using ozone in the air to kill unwanted bacteria, viruses and other microorganisms (including Covid) for years.  Will it work in liquid? Mead is a remarkably stable drink in the presence of oxygen so after some correspondence with the owner of an ozone machine manufacturing company for the beverage industry, we concluded that it was worth a try.

It worked! I added ozone directly to the batch like I was running a CIP procedure and it killed everything! Not only that, when I took samples out to our staff and regular customers, they tended to prefer the batch that was processed with ozone.

What a relief.

We now use Ozone as part of our standard mead making process.  As an added bonus, when used on the fresh must, to wipe the slate clean before I inoculate with my own yeast strain, it all breaks down into O2 which makes the yeast very happy.  They multiply more rapidly and, so far, it seems that I can knock an entire week off the ferment time.  A Win-Win.

Now here I am with almost 2,000 gallons of lovely – and stable – sour mead that we can’t use in any of our current products.  What to do? What to do? Oh Bother, what to do?

Stay tuned…