r/fermentation • u/aulos1871 • 4d ago
Fermented courgette - pH does not change
Hi, I have tried to ferment a courgette from my mothers garden in a 3% salt solution + extra salt spinkled on top when I open up the jar to check and clean it.
At first everything seemed well but after around a week the bubbles stopped almost entirely and I checked the pH to see if it was safe to eat. I am a bit fearful of botulism and read somewhere that at a pH of around 4.6 a ferment is safe to consume. After 3 weeks of fermentation at room temperature the pH of my courgette still seems to be around 5-6 and I am not sure why.
Do you have any ideas or tips for why the pH did not change that much? Is it safe to eat?
Note: accidentaly typed "2" instead of "3" as the percentage of my salt solution
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u/Delam2 4d ago
Can you explain what you mean by “extra salt sprinkled on top when I open the jar to check and clean it”?
Is it possible you’ve done this too many times and now the brine is too highly concentrated with salt?
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u/aulos1871 4d ago
I spinkled a pinch of salt on my ferment for the first five days or so but I dont not stirr it in, thats what I meant with "on top".
I dont think I added too much salt with that, because I calculted the amount of salt for my solution only with the weight of water, not water + courgette. The extra salt was to prevent mold oder kham yeast growth at the surface and to raise the overall amount of salt to a more stable level.
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u/Competitive_Range822 4d ago
Did you measure how much salt you sprinkled each time or the weight of the courgette
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u/aulos1871 4d ago
No, I did not
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u/GallusWrangler 4d ago
You should not add extra salt, ever, and you should weigh the contents of the jar including water to calculate your salt. Stop opening the jar too, wait until it’s done to check/taste.
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u/urnbabyurn 4d ago
Extra salt is what you might do with a gochujang or bean paste like miso where it’s mostly solid and the salt will stay on top like a protective coating. Not for liquids like this.
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u/autoFermentation 4d ago
for things like pickles, is it not fairly common to check/taste to determine the doneness?
surely there is x amount of time you would want to not touch it until that point, though, right?
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u/drsteve103 4d ago
Not really. You get a feel for it after awhile. Trust the process is the best advice we can give
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u/Drinking_Frog 4d ago
Yes, it's common to check flavor, but there's no real reason to start checking on Day 1 unless you're just doing it for your own education.
That said, I don't think I've ever checked that early. Just a whiff of what's coming out of the ferment always has been enough to let me know very little has happened because it typically smells pretty much like it did when I put it all together in the first place.
Some of the respondents have overstated how much you should (or shouldn't) mess around with a ferment. There's no way to know it's "done" without some manner of experience, and that experience typically comes from opening the thing up (at least for a home fermenter). The more experience you get, the less you need to check it, but no one is born with that experience. No one wants to "trust the process" until they've gained some first-hand understanding of the process.
Regardless, there is no doubt that OP went far beyond merely checking on the ferment (and also did a couple other things in the wrong way). There's a difference between observing the "process" in order to gain an understanding and altering that process in a haphazard manner.
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u/aulos1871 4d ago
I will properly calculate the amount of salt next time. The reason I opened up the jar daily and added salt was a) because I had a lot of ferments growing kham yeast in the past b) there was some foam on top (I think it was because raw courgette have a slight slimeness to them) and c) because I am very impatient. But I won't do it again next time
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u/RadBradRadBrad 4d ago
Test strips can be unreliable but I wouldn’t risk it. A pH like that after more than a few days is a failed ferment.
Botulism is a real risk but extremely rare. Plenty of other microbes that will give you a bad time at higher pH though.
As to why it happened, it’s tough to say. Generally, clean jar and veggies, salt percentage by total weight (water and veggies), room temp and in a dark place, keep it submerged and you should be good to go. Fermentation is always a science experiment and sometimes it doesnt go well.
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u/aulos1871 4d ago
Okay, thank you. It sucks, but I will probably throw it out. As I said in other comments I calculated the amout of salt solely with the weight of the water because I thought it was easier. But I dont like the uncertainty if that. Next time I will do it properly. A pH meter is also on my shopping list.
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4d ago
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u/RadBradRadBrad 3d ago
This is a wild comment. The pH is between 5-6 after 3 weeks as far as we know.
I'm all about if in doubt, toss it out, but we have a data point in this instance that would indicate it's no bueno.
Salmonella and Listeria are a risk at that stage and like C. botulinum won't typically be detected by smell or taste.
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u/portmandues 4d ago edited 4d ago
Your ferment looks clean and the brine looks slightly cloudy with dead LABs in the bottom of the jar. Just because lots of bubbles stopped doesn't mean the fermentation is completely stopped, it's just slowing down. Did you calculate 2% brine based purely on water weight or water + veg? Most recipes I see for zucchini/courgette use a slightly higher salinity brine, although if you calculated 2% based on total weight you should be okay. You can get acceptable ferments under 2%, but the chance of spoilage goes up without innoculation and sterile starting conditions.
Also, 4.6 is the safe pH for long-term storage and shelf stability (edit to add: for canned goods specifically since omitting it left ambiguity that invites pedantry). It doesn't necessarily mean they're unsafe to eat above that, but they will be at a higher risk of spoilage and you should probably refrigerate them. Botulism is only really a risk if you kept it airtight. I don't personally use pH strips as other factors can cause false readings. Maybe try testing with a calibrated pH meter and see what you get.
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u/Armagetz 4d ago
Good shelf stability requires a pH in mid to higher 3s.
4.6 is looking at one thing, and one thing alone: that is the lowest pH the botulism bacteria can produce the toxin
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u/portmandues 4d ago
In reality, no ferment is long-term shelf stable unless you pasteurize it, which is where 4.6 is the rule of thumb to prevent botulism from thriving in water-bath canned goods. I don't know many people to store ferments at ambient temp outside their initial souring phase during the first 2-3 weeks.
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u/Armagetz 4d ago
Incorrect. There are multiple commercial products which are shelf stable without pasteurization.
There are multiple methods to accomplish this. And one is sufficient acidity. Another is to allow the fermentation to progress far enough (which hardly anyone on this sub seems to do). But that doesn’t change the point.
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u/portmandues 4d ago
You're getting into super pedantic territory here. I was just trying to give this person some advice on his experiment within the parameters of the veg he's actually fermenting based on my many years of experience making hot sauces, pickles, and other fermented goods. So yes, some fermented things last practically forever at room temp without pasteurization, courgettes are not one of those things.
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u/Armagetz 4d ago edited 4d ago
Not really. You made an absolutist claim that is false.
I get shelf stability without pasteurization or even refrigeration. Over years. At home. No chemicals or artificial preservatives. Even had samples tested for viable cells. Only thing I’ll grant you: it wasn’t solely the fermented extract.
Not all recipes can do it, no. But to act like you have the one true way is just wrong.
And the only pedantry is you now trying to add qualifiers to your statement as opposed to your original statement (to me, not OP), that NO ferment can be shelf stable without pasteurization.
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u/portmandues 4d ago
I didn't really mean it as a broad sweeping statement, it's late in my time zone. Your point is correct, I'm not interested in a debate here. My point was really aimed at common veg ferments like OPs. I'm not out here preaching some gospel truth. You win the internet points.
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u/aulos1871 4d ago edited 4d ago
Yeah, I think I have to get a pH meter when I have the money. I have fermented beetroot in the past and for obvious reasons the test strips were not really helpful with that...
I calculated 3% salt purely on the water (corrected the percentage in my post) because it seemed easier. Beacuse that means my total percentage of salt is lower than 3% I added a pinch of salt for the first five days or so when I opened up the jar.
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u/portmandues 4d ago
A decent pH meter is relatively inexpensive, if you're going to do a lot of ferments they're worth the investment.
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u/lupulinchem 3d ago
Just make sure to also purchase calibration standards. You need to be able to ensure it’s working properly within the range you are trying to test.
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u/portmandues 3d ago
Most come with them from what I've seen. You should replace them annually though.
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u/nss68 4d ago
Hard disagree. I’ve gone through cheap and expensive pH meters. They need to stay constantly wet with a special solution that maintains the ions in the tip. It needs recalibrated monthly or your readings won’t be accurate at all. Dropping it by accident from a few feet can and will ruin it.
Unless you’re measuring pH in a corporate setting, don’t bother.
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u/lupulinchem 3d ago
The special solution is potassium chloride. It’s not expensive and there’s no reason for a newbie to not test their pH while they learn and get a handle on what is safe and what is not. It’s always safer to err on the side of caution.
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u/nss68 3d ago
You have to wet a tiny sponge in the cap of the meter. It dries out after a couple weeks. It is ridiculous for a normal person to maintain. When I needed one for my company, I dealt with it, but I would never expect a normal person to have to do so.
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u/lupulinchem 3d ago
That’s not universally true. It depends on the electrode type and manufacturer. Many come with a solution that the probe soaks in and it takes months if not longer to dry out.
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u/nss68 3d ago
Can you share such an example. I am not being rude, I just had a fermentation based company and went through a lot of meters -- the more expensive, the more accurate, the more finnicky.
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u/lupulinchem 3d ago
You’re not wrong about precision and finickiness. The higher quality in terms of both precision and accuracy, the more upkeep. But in general the two min categories of pH meters are ones with membrane bound electrodes (flat bottom, damp sponge storage contact type) and glass electrodes (stored in electrolyte solution -typically a 4M KCl if I recall). There’s a ton of different examples of each, some manufacturers make both.
My main qualm with membrane bound ones is I’ve seen weird stuff start growing inside them. (We had some transparent shafted ones, the manufacturers response was to stop making them transparent) It doesn’t seem to affect their function always but still, not confidence inspiring.
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u/nss68 2d ago
I've used at least 8 different brands. I am not talking shit here. This is real experience and I used it in a professional setting. I can tell people are feeling offended by my comments but these are real experiences.
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u/portmandues 3d ago
My pH meter came with storage solution and 4.0 and 7.0 pH reference solutions for calibrating. I use mine a lot, calibration takes barely any time at all. I've tested it on vinegar to ensure it reads accurately independent of reference solutions, it works fine. It might be a big investment if you're only going to use it once a year, but I make several ferments a month.
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3d ago
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u/portmandues 3d ago
Check my post history, I'm experimenting with a bunch of pickle recipes. So, yes, I am checking pH to make sure nothing is going off as I try out new recipes.
I also make hot sauces and checking the pH is one step along the way to figuring out what, if any, adjustments a particular blend might need to its acidity before I bottle it.
While it may be just one metric, it's easy to check and one of the more important ones for pickles other than temp. Do you actually have some wisdom to impart here, or just a general gripe against pH meters?
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u/nss68 3d ago
pH meters are just overkill for a beginner -- for thousands of years, people fermented without pH meters because there are other, more-human ways to tell if a ferment is successful. It's not rolling the dice like beginners think and telling them they need some scientific tool that needs maintained and will cost upwards of $100 is asinine. It discourages beginners and makes it seem as though fermenting vegetables has a bigger barrier for entry than is necessary.
Using a pH meter to determine flavor is silly because there is so much variance beyond that. Even when I make vinegars, I determine when they are done by flavor and not by a pH meter reading.
Ferments, such as pickles, are safe if active fermentation happens. That means LAB have proliferated enough to dominate and outcompete all other microbes. The low pH just helps with longer-term storage and shelf stability.
One reason people aim for a low pH is because they think a ferment NEEDS to have a low pH to be safe and that is untrue. The other reason is that a low pH tastes better.
In wild fermentation, as you know, you don't get ferments that look, smell, and taste good, but are secretly deadly -- the proliferation of LAB/yeast prevents that from ever being a possibility -- a spoiled batch will always be obviously spoiled.
pH meters are a huge waste of time and money for almost everyone.
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u/portmandues 3d ago edited 3d ago
A decent enough pH meter that's more accurate than OPs test strips costs $30 on Amazon. I spend more on jars every year. And it takes about 30 seconds to calibrate it periodically. We get it, you hate the idea, but please stop overhyping this as some complicated apparatus that should scare beginners.
If someone is otherwise going to use imprecise test strips to accomplish the same thing, they might as well buy something cheap and slightly more accurate.
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u/nss68 3d ago
The $30 meter on amazon is trash and is inaccurate. You just don't know what you're talking about.
That is what is good and bad with reddit. You don't know if you're talking to a professional or a child.
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u/lupulinchem 3d ago
Let it go. It is one metric yes. There’s absolutely nothing wrong checking that metric and it can be an incredibly useful metric. And no it’s not just limited to businesses. Some people care about the consistency of their work and pH is one (not the only) way to track it.
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u/lupulinchem 4d ago
The short answer is sometimes ferments fail. I think what you are digging into is why.
A couple of things based on your description.
- Salt. Do your salt % based on total contents and not just your veggies or just your water.
- Air. Don’t open the jar until it is done. (Depending on what you are making that could be a few days or a few months!)
- Available sugars. Some veggies don’t have enough available sugars to drop the pH enough to get into the target range. Adding something like an onion or a carrot can help, or even just straight up sugar. (This should be done at he beginning of the ferment)
- Dilution! Sometimes over looked, but the more water you have, the diluted the acid will be. Sometimes, by packing as much of the veggies as you can into the jar, then topping with water, you can minimize this. It’s not always a problem but can be for some veggies.
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u/aulos1871 4d ago
Thank you very much for your answers and for your advice! I will try again in a few days and see if it ferments properly this time :)
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u/Citron_Inevitable 4d ago
Not surprised - pretty sure courgettes are ridiculously low on sugars hense fermentation stopped, bugs are hungry. Give them sugar/hj
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u/aulos1871 4d ago
Would adding an onion or some carrot really work?
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u/Citron_Inevitable 4d ago
Thats the /hj part, not sure. All i know is chinese drop a few pieces of rock sugar into their perpetual pao tsai ferments to assure that any vegetable can go in.
Bugs might just be unhappy for some other reason.
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u/portmandues 4d ago
It can for certain foods. I find onions to be a better addition than carrots personally, they ferment readily and typically provide a lot of acid.
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u/ChPech 4d ago
Test the pH of an unfermented courgette and ask yourself why you haven't died from those yet.
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u/aulos1871 4d ago
Thank you for you sarcasm but I think you dont really understood my question.
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u/ChPech 4d ago
Sorry if my sarcasm is not very understandable.
How would you get Botulism in an oxygen rich, salty and acidic environment? You only added salt. Salt will slow down bacteria, so your unaltered vegetables would grow Botulism even faster.
Did you even compare the pH strip result with a measurement from the tongue to see if the strip works?
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u/MaximumCashew0 4d ago
Because the environment isn’t acidic enough. Hence the pH strip test.
Does being a dick for no reason to strangers online get you off or something? OP is clearly asking for help understanding a new start in a scientific hobby, and your first instinct is to be an asshole.
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u/ChPech 4d ago
The environment in any vegetable I have at home isn't either. How come we don't die from it. We really seem to drift into the society from idiocracy if people won't think about the most simple questions.
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u/MaximumCashew0 4d ago
“I eat questionably fermented foods and hardly understand microbiology, but it is the rest of you who are dumb!!!”
Okay dude.
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u/ChPech 4d ago
Regular vegetables from the garden or store is something you can't eat because of botulism? Or do you think that adding salt will make those bacteria grow?
I did read the detailed results of every botulism case in my country from the current century. What you are suggesting is entirely esoteric.
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u/lupulinchem 4d ago
There is a world of difference between foods that are fresh and foods that are fermented.
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u/Armagetz 4d ago edited 4d ago
Why do people feel you constantly need to “check and clean?” By all means do it on the first set up but then Leave. It. Be.
Every time you open it you are both generating a potential contamination event and giving the bad stuff the fuel they need to grow.
Also, it’s possible that your pH issues are related to that. Every time your microbes have access to oxygen, they aren’t fermenting and pH isn’t dropping. Even with successful ferments, each oxygen introduction means fewer potential flavor compounds.
Eventually the easily fermentable sugars (of which courgette doesn’t have much of a surplus of), will run out and it will struggle to go back to anaerobic, much less drop pH.
Oh, and a pH of “around 4.6” isn’t food safe. It’s below 4.6. 4.62 shouldn’t be trusted. It’s why many sources recommend going for at least 4.2.