Whey, and starters in general, are a topic of controversy among many in the fermentation world. Well loved books like Nourishing Traditions call for its use in nearly every fermentation recipe, while other well-established voices advise against using it, noting that vegetables are covered in their own starter culture (just add some salt or salt water), that starters may lower pH enough that first stage organisms are bypassed, that the organisms that ferment dairy are distinct from the organisms that ferment vegetables – a point I quibble with a little bit, and, in what strikes me as among the superstitions of fermentation, that using whey or starters can cause “pH drift,” or even make a ferment’s pH impossible to measure because (magically?) it’s changing so rapidly that measurement tools are foiled.
So why do people use whey or starters in vegetable ferments? Although they aren’t necessary, there are a host of reasons, from wanting to reduce the amount of salt in a recipe to believing that it’s a more foolproof method. If you make a lot of cheese, yogurt, or kefir, you may find yourself awash in whey and just want to put it to use. Starters are also recommended when making ferments from cooked foods, like fermented apple sauces, roasted peppers. Whey is also helpful in kicking off fermented beverages from fruit and vegetable juice.
In the Wild Fermentation Uncensored Facebook group, group founder Johann Kuntz decided last fall that this is a topic that members in the group could look into themselves and proposed a citizen-scientist type experiment to explore the topic. This is a write-up of the results of our experiments, and while we’re not going to be nominated for any Nobels for this work, it was interesting and informative to approach the process this way.
Fermentation Starter Experiment Design
The design of the experiment was simple: choose a vegetable to ferment, prepare enough of it for (at least) two fermentation jars of equal size, and retain “Lot 1” as your control, i.e., Lot 1 will use only salt or salt water, depending on what you’re making. Lot 2, and up if you’re dreaming big, will use a starter of some kind. At the outset and, if you’re not using an airlock, along the way, test pH with litmus paper or a pH meter, as well as at completion. I ran two versions of the experiment with matchstick turnips in brine. One test batch used whey from store-bought Greek yogurt, and the second test batch used a cheesemaking starter containing an organism called Lactococcus lactis. After reading this Croatian paper analyzing the results of four different approaches to sauerkraut production, I’ve been very interested in L. lactis.
According to the authors,
“The best sauerkraut quality was achieved by introducing starter culture L. lactis ssp. lactis into the fermentation process. On the 7th fermentation day (initial fermentation was 5 × 108 cfu/ml), the number of these bacteria dropped to 0.3 × 102 cfu per ml and they were not found later in the medium (Figure 4). This is in accordance with the results of the investigation conducted by Anonymous (1993) and Battcock and Azim-Ali (1998) who reported that L. lactis ssp. lactis survived for a short period only in the medium. However, its presence lasts long enough to initiate sauerkraut fermentation process without disturbing natural microorganisms sequence.”
I bolded that final bit, since according to the paper, L. lactis fully answers the objection of “skipping” the early-stage fermentation organisms like Leuconstoc mesenteroides.
I’ll share pictures of how the pH changes showed on litmus paper I bought for the experiment, but to skip the end briefly: Don’t put litmus paper directly into your brine. All four of my batches grew mold and none made it to the tasting stage. Always remove brine with a clean spoon or pipette for testing. Yeah, clearly I’m not ready for my Grown Up Scientist badge.
Acidification with Whey Starter
These are images showing the ferments at 24 hours, 72 hours, and 9 days into their process. As you can see, both acidified satisfactorily. My contemporaneous notes a few days in say, “Since Saturday, the control [with no whey in it] has been quite frothy. The test jar has been less frothy on the surface, but appears to be making more CO2 (inflating the weighted baggie airlock) and a bit cloudier.”
Acidification with L. lactis Starter
This one, started a week or so later, was mind blowing to me. The Lactococcus lactis starter dropped the pH faster in a measurable way, in spite of the fact that litmus paper isn’t… the gold standard, let’s say. Here’s the photo recap:
As you can see, L. lactis as a starter seems to have real promise for quick acidification, so for people who have excessive concerns about food safety, this might be an option to engage in fermentation while addressing that concern. I’m sad that I wasn’t able to get these to the tasting stage, but plan to revisit L. lactis in a side-by-side in the future.
For Johann’s experiment, he went with sauerkraut, one batch with only salt and one batch with salt plus whey from mature milk kefir. He recorded initial pH, with litmus paper, as around 5 for the control and between 4.0 – 4.5 for the test batch.
Both acidified properly, with his recording the final pH in the neighborhood of 2.5 (which is quite a bit more acidic than researchers usually find). He felt that the whey batch did, as many report, leave a tell-tale taste. “I will say the batch with the whey developed a slight undesirable flavor which I think came from the breakdown of its proteins rather than from the fermenting organisms it brought with it,” he wrote.
- Don’t dip litmus paper into your fermentation vessel. This should have been a no-brainer, but I have some moments of real knuckleheadedness.
- Based on this very small experiment and ample reading of research papers on these topics, there’s no evidence that using whey or starters causes pH to move in the wrong direction or, more fantastically, to spin wildly and become impossible to measure.
- Whey can impact flavor and texture (this is backed by numerous anecdotal reports online). Whether this is good or bad really depends on your tastes.
- Whey and commercial starters are a safe option for people who need or prefer low-salt options for fermentation.
- Finally, and I really can’t stress this enough, DON’T DIP LITMUS PAPER INTO YOUR BRINE IN THE JAR! Should you want to replicate the experiment and see what you find, which you totally should. (Email me with results or a link to your post if you do!)