I received the following question from Josh this morning (thanks so much for the question!):
But I’m hoping you can clarify that for me based off your experience. I cold pickled some cukes a while back. The other day, I finished the jar and added a new batch of fresh cukes to the brine. Leaving it out on my counter top overnight, I was surprised to wake up in the morning to find that the fermentation process had kicked started and was in full action.
Now is this safe? Can I maintain this brine and use it over and over again? Or is there a sweet spot where the brine stops working and I venture into dangerous territory?
I thought this would be a topic that many of you would be interested in, so I thought I’d answer his question here.
Let me start with the safety issue: I really can’t give solid advice on the safety; I am not a food scientist and everything I write here is what I believe to be 100% safe or I wouldn’t eat it myself (or serve it to friends and family). When it comes to safety, I am conservative and I do a lot of research, reading and learning about preserving. But I’m also human so I can only answer that I believe this to be absolutely safe. To read more on why I hesitate to answer on safety, you can read this.
Lactic acid fermentation uses oxygen and botulism (the most common fear of preservers) thrives with the lack of oxygen. Sandor Katz (who is known as the “Godfather of Fermentaion”) maintains that you can’t get botulism from preserving. There’s a thorough discussion of the topic in his forum written by another user here. Canning, which is associated with botulism, is something to be concerned about but the fear is often exaggerated (you can see the actual stats around botulism and home canning in this article).
Rather than declaring the re-use of brine safe (which I don’t think I’m qualified to do), I’ll answer the safety question the most honest way I know how: I believe it to be safe, would not be concerned with it, I am open to being corrected and advise you to do your own research as well.
NOW, TO THE QUESTION: CAN YOU RE-USE A BRINE?
Yes, yes, a thousand times yes – with a few cautions:
- When you ferment, you encourage the growth of good bacteria (including probiotics; a term that the yogurt industry has commandeered as their own). Placing it in the fridge slows the ferment (which allows the texture and the flavor to stabilize) and the bacteria slows down. The bacteria will become more active when brought back to room temperature – to a point. The bacteria will eventually die and the liquid can be used to ferment but will not be substantially advantageous compared to plain water (other than taste).
- Fermenting pickled carrots are great (there’s a version with mustard seed here). Re-using the brine to ferment carrots would be super. But be cautious using the brine to ferment hot peppers – it will work but the taste could be, erm, experimental (I’d ferment cabbage in carrot brine though!)
- If you’re adding liquid, measure the liquid and the salt of the added liquid before adding it to the brine (most ferments are 3-5% salt-to-water by weight).
- You can add a little bit of brine to another ferment to start the process going (kind of like the process of creating a ginger bug to make ginger beer or fermenting hot sauce with whey)
So there you have it! Would you re-use brine when fermenting?
Giant thanks to Josh for the question (you can send yours on our contact page; we’ll do our best to answer all we can!)
Edit – May 1, 2014. We received another question along the same lines today and added another article with similar, but different perspective. You can check it out here if you want more info/ ideas.