Taking A Deep Breath

Welcome back to this tenth installment in my essay series about fermentation – and what it has to offer you, both in edible and in non-edible ways…

In the last essay, we talked a lot about gases, and in particular about gases which are produced during fermentation and then have to go somewhere (lest your vessels might explode), hence the need for air locks of all sorts.

Today’s essay is a bit less explosive, but no less gaseous. It’s also somewhat smellier, at least in some places. And lo and behold, air locks will have another grand appearance, too!

You remember what an air lock is, don’t you? An ingenious device, constructed such that the gases produced by a ferment (inside a vessel) can leave said vessel – instead of creating ever more overpressure inside, and eventually an explosion.

Such air locks can come in various forms, and a lot of them make use of water as a “barrier”. E.g. for sauerkraut pots, it’s a water filled rim, closed by a fitting lid. For wine demi-johns, it’s a plugged-in pipe in the form of a “U” whose bottom curve is filled with water (as in the U-shaped drainage pipe below your sink).

Mason jars, in turn, don’t make use of water, but of a rubber seal between glass jar and glass lid, so that the lid can be lifted ever so slightly, and gases can escape.

No matter the practical implementation, when you use an air lock for fermentation, overpressure inside the vessel (e.g. in the form of carbon dioxide) can bubble out through this barrier.

But why does it take such clever devices at all? Why not just leave these jars and vessels open, or only losely cover them with some cloth to keep flies and dust out?

Well, that’s a very good question – and it leads us straight into the heart of todays’s essay… 🙂

You might not remember this (or you might, for that matter! 😀 ), but way back in one of the very first essays, we talked about scientific definitions of fermentation: What, exactly, counts as fermentation? And what other processes might be similar, but are different enough to not be called fermentation anymore?

Back then, we realized that the border is blurry. And one of the areas where the grey zone is particularly broad is… oxygen.

Or, to put it into technical terms: Are fermentation processes by definition anaerob (i.e. without making use of oxygen)? Or can aerob processes, i.e. ones which make use of oxygen, also rightfully be called fermentation?

As we concluded back then, the answer to this question depends – on whoever is putting up the definition, and for which purpose. And as I explained back then already, I’m not trying to give scientific explanations in this series.

Instead, its focus is on practical, hands-on fermentation and on Inner Fermentation, with loads of bits and pieces related to various other topics thrown in. Like, for example, the history of fermentation, health issues, matters of taste, or the sheer joy of experimentation.

Still, if you have done your past few homeworks (or even if you’ve only read their instructions), you will have noticed that there is some inherent importance to this issue of oxygen or no oxygen. After all, the question of when to keep your ferments out in the open, when to stir air in, and when to lock out the air, this question came up time and again.

So what does this mean? And why is it sometimes important to expose your ferments to the air, and sometimes important to keep them away from air – and sometimes to do first one and then the other, depending on the stage of fermentation?

You see, a fermentation culture is a living, breathing thing. This isn’t just a metaphor, by the way: In some ways, your sourdough and mead cultures really do breathe out and in, just like we do.

But they function in ways which are different from ours. We’ve encountered this before, back when we had a closer look at fermentation critters’ food.

Their breathing is different from ours, too. Come to think of, this isn’t really surprising! Take, for example, trees. Although they are much closer to humans than tiny little fermentation critters are, they still breathe in a different way – thankfully, I may add, as this is what makes live on earth even possible in the first place!

Trees also breathe out and in, just like we do – only that they breathe in what we breathe out, namely carbon dioxide. And they breathe out what we breathe in, namely oxygen. Neat, huh?

So what do these wee fermentation critters breathe in and out?

Well, as so often in this series, it depends. 😉

We already talked about their outbreath last time, so to speak, i.e. about the gases they produce while they ferment feed on the sugars in your base material. And while I only hinted at it by using terms like “carbonation”, you might already have inferred that fermentation cultures breathe out carbon dioxide – and you’d have been right.

(Yes, one could indeed draw the conclusion that contrary to outer appearence, humans are more similar to fermentation critters than to trees, at least in this regard… 😉 )

But what, then, do they breathe in? Oxygen, just like us? And this is where things depend…

So far, we’ve (or, to be more precise: I have) been talking about fermentation critters as if there was only one kind of them. The Common Fermentation Critter, or Fermentatio communis. 😉

But in reality, this isn’t true. Just like there are many kinds of trees, there are also many kinds of fermentation critters.

Some of them appear (and work) together or at least alongside each other, i.e. in the same kinds of ferments. Some of them specialize in different stuff, and thus don’t belong to the same fermentation cultures.

The latter, btw, doesn’t mean they can’t appear in the same kind of ferment – but not in the same culture at the same time.

(Strictly speaking, of course they can “appear” together. A fermentation culture can be dominated by certain critters, while others coexist on the side. What I’m talking about here are thus the critters which define a specific culture, at a specific stage, and do most of the heavy fermentation lifting in it.)

Take, for example, some of the drinks you have (hopefully 😉 ) brewed as part of your Hands-On Homeworks. Generally speaking, the Homework instructions were all remarkably similar:

1. Mix everything together, and leave it out to ferment in the open, only losely covered.
2. Stir, stir, and then stir some more.
3. Once the bubbling is getting less, sieve (if applicable) and fill into (losely!) capped bottles or into vessels with air lock.
4. Leave in this vessel to ferment some more, a few weeks or potentially even longer.

There are other details, of course, e.g. about racking if you go the “mature fermented drink” route and let things continue to brew away in a demi-john or simlar vessel. But essentially, this is it.

And with regards to our topic at hand, there are three distinct things to note in this general “recipe”: two stages, and an action.

The first stage comprises the first few days. Your budding drink stays out in the open, only losely covered against flies and other unwanted things. The fermentation culture has free access to air, and thus to oxygen.

The corresponding action is stirring.

Each time you stir, more air (and thus oxygen) enters the liquid. (Have you ever whipped up cream? Yeah, like that…)

Consequently, the fermentation critters which thrive in this first phase love oxygen – they breathe it in, so to speak.

(Strictly speaking, they metabolize it in other ways. But c’mon on, the idea of them breathing is such a nice image, and we don’t have to be pedantic, do we?)

By your stirring, you add even more of that precious oxygen, thus supporting the very cultures which thrive on it. And consequently, their number increases (or rather: explodes). These critters breathe in the oxygen, and breathe out carbon dioxide – your ferment boils and bubbles away happily.

But hang on, then why does the bubbling subside at some point?

Well, all this breathing is nice and all that, but of course these poor little guys also have to eat, right? And eat they do, converting all these delicious sugars right into acidity.

These critters live in the land of plenty, with food and oxygen galore – and consequently, they procreate like rabbits little fermentation critters are wont to do under ideal circumstances. Which, in turn, means that a lot of the sugar is used up, and your ferment gets ever more acid.

Or, in other words: The conditions inside your ferment change over time, with ever more acidity and ever less sugar. This, in turn, is a lot less ideal for some of these eager little beavers. The number of said critters reduces, there is correspondingly less of their outbreath – and the bubbling subsides.

Now, as we’ll dicuss at a later point in the series, a fermentation culture is a complex thing, and there isn’t just one kind of critter in there. And just because some of them are less happy in this slowly changing environment doesn’t mean all of them are, quite the contrary!

There are other critters in there which are very keen on taking over, now that your ferment finally has the conditions they enjoy.

Thus slowly but surely, the nature of your fermentation culture changes. What were once the predominant little critters are now becoming a marginal part of the fermentation culture’s hotchpotch, and what were once marginal and might barely have survived are now becoming the dominant element.

Left to their own devices, these now dominant little buggers would continue to do what they love: Eat up sugars, and produce ever more acidity. After all, they thrive in a more acidic environment.

(To some extent at least – we all have our limits to what we can tolerate, and these little critters are no exception!)

Consequently, if left to do the job, they’d turn your brew not into the delicious alcoholic tonic you imagined, but into something vinegar-like. Which is nice and all that, of course, (a good vinegar is an awesome thing) – but not if you want to enjoy some herbal wine or share a pitcher of cold mead with some friends.

So you need to stop this second group of little guys from going overboard. Thankfully, this is easy enough, as in order to ferment away and eat up sugars, they need oxygen.

Thus your ferment enters the second, anearobic stage, the stage where you put it behind an air lock. Or, if you don’t want to store your fermented brew for long and intend to drink it rather young, into simple, losely capped bottles – closed enough to keep most of the air and oxygen out, but open enough to allow overpressure to escape.

This is a massive change in environment, of course. For the wee critters, it’s comparable to a massive onset of winter in the middle of July (or January, if you live on the Southern half of the globe).

Luckily, your fermentation culture is an astonishingly resilient thing. Or rather, wild cultures are – artificial cultures are a different matter, but we’ll have a closer look at them and at this distinction in general another time.

For today, we’re concerned with the cultures you have encountered in your Hands-On Homeworks, and they are all wild cultures and consist of many different kinds of wee critters. And as I said, thankfully!

Because when you change their environment so completely and abruptly, quite understandably, the kinds of critters which thrive in acidity (and need oxygen to digest sugars) go off sulking in a corner.

In fact, they are so miffed by this that they refuse to procreate any further. Well, mostly – there is still some oxygen left in there, after all, and they can’t help themselves… 😉

(You can easily determine that the oxygen-loving critters don’t all die off, btw, even if your ferment stays behind an air lock for some time. Just rack your brew, thus adding oxygen, and things will start to boil again, although maybe not quite as violently anymore than before…)

But in their stead, other critters now peak out from the obscure corners of your brew where they’ve been hiding, and after a quick look around, they start jumping up and down in glee – because this new environment is exactly what they ordered.

And of course, being wee fermentation critters, they do what such critters do best, and start eating, breathing and procreating right away. And just like the earlier dominant groups of critters excreted acidity, this group now excretes alcohol. (They still pass gases, too!)

Thus, in the depths of your losely capped bottles or your air-locked demi-john, your brew is slowly getting more tart (as sugars are still being eating up), and more alcoholic.

Eventually, though, this process also comes to a stop. At some point, the alcohol content is becoming too much for most of these later critters, and they, too, slow down ever more.

When exactly that is the case does, again, depend. (I know. I use this word a lot! 😀 )

Since we’re working with wild cultures here, we can never exactly tell which kinds of critters are in there. And as some of them can stand more alcohol than others before they slow down or even pass away, thus some of your home-brews will develop more alcohol than others – depending on which kinds of creatures were part of the respective culture in the first place.

We’ll talk more about these complex cultures later. For now, though, let’s focus on their breathing again…

As you can see, the question “What do they breathe in?” doesn’t have quite as simple an answer as the question “What do they breathe out?”. Some fermentation critters need oxygen, and some can hardly stand it (if at all).

And just to add to the fun, there are also some which can adjust their metabolism. They thrive with and without oxygen, but depending on its availability, they digest sugars in different ways, and with different results.

Some of the critters which excrete alcohol belong in this category: They only produce alcohol if they have to digest their food without some oxygen on the side.

In any case, as long as you’re working with wild fermentation cultures, there are a lot of different critters in there. Which ones dominate at any particular stage depends on the conditions these little guys find themselves in: acidity and alcohol content, for starters. The availabilty of food (i.e. sugars, starches etc) in general, and the specific kinds of food which are available.

These things form the environment to which your fermentation culture has to adapt. And adapt it does, with vigor and enthusiasm. No matter how the environment changes, as long as some of your wee friends can adapt to it, they’ll pick up the baton and carry on fermenting.

This doesn’t mean that all the others die off immediately, though! No matter what the current conditions are, some of the less well adapated critters will oftentimes survive alongside the then-dominating majority. And once their time comes, they procreate with amazing speed and enthusiastically take over the fermentation process, while the critters which were dominant before now become a fringe minority.

We’ll have a closer look at the environment next time, and in particular at an important environmental condition we haven’t much discussed yet.

Before we wrap up for today and dive into your Homeworks, I need to clear up a potential misunderstanding, though:

Throughout this essay, I’ve presented the different stages as clear-cut, and the corresponding fermentation cultures as more or less distinct. This isn’t entirely true in real life, though.

For example, some alcohol can well develop in aerob conditions, i.e. when oxygen is available. It can be hard to tell in mead or herbal wine, as the sweetness is still so predominant at the beginning, but you might have encountered this with sourdough or other grain-based cultures which sometimes develop a slight alcoholic taste or smell.

And just as some alcohol can develop under the aerob conditions, so can the acidity in your ferment still rise once it’s air-locked, i.e. when deprived of oxygen.

What I’ve been describing here in this essay are some of the predominant processes, particularly in fermented drinks. But as always, real life is a lot muddier and a lot less black-and-white, with all shades of grey and all colours of the rainbow thrown into the mix. Thus depending on your actual cultures, things might vary quite a bit!

We’ve talked a lot about the metabolism of fermentation critters today, and in particular about what is their analog to breathing: Carbon dioxide on the outbreath, and oxygen on the inbreath – at least for some of them! 😉

I guess we really could say they are somewhat more like us in their breathing than trees are – but on the other hand, they’re also weird and diverse, and a category all of their own…

Remember when I quoted that adage about how one can survive for two minutes without air, for two days without water, and for two weeks without food? While this is a rough guide for humans (give or take a bit in some of the numbers), fermentation critters are a lot more varied:

They need food a lot more than we do and can process it much faster, but at the same time can survive much longer without, as we will see in a later essay.

They don’t actually drink water, but rather need at least some of it to live in (dry noodles won’t ferment, whereas boiled, wet noodles can turn sour under the right conditions, for example).

And as to oxygen… some of them need it to thrive, some will only thrive without it, and some can do both. Weird (and interesting!) little buggers, huh? 🙂

This is it for today, folks, at least in terms of this essay (we’ve still got your Homeworks to get to!). We’ve covered a lot of Air today, with a sidenote of Fire (in the boiling) and Water (in all the brews we focused on). The Hands-On Homework will also introduce a dash of Earth, just to balance things out. 😉

In the overall picture, we’re still very firmly focused on the big In-Between, i.e. that which happens to turn an un-assuming base material into an exciting, healthy and tasty ferment.

This process, its details, lessons, and intricacies will keep us busy for yet another few essays – and in the next couple of them, we are going to have a closer look at some other environmental conditions which are just as important as the question of oxygen.

Oh, and one final thing: I know we’ve been focusing a lot on fermented drinks lately. I promise this is going to change again soon – we will explore our fair share of fermented foodstuffs in this series, too! 🙂 First though, today’s Hands-On Homework is going to be something else entirely…

Inner Fermentation Homework

We’ve talked a lot about fermentation’s (metaphoric) inbreath and outbreath today, and in particular about what these little critters breathe in and out.

I guess you thus won’t be surprised when I tell you there is an inbreath and an outbreath in Inner Fermentation, too. 😉 Your Homework for the next two weeks is to explore them:

• In which ways is the breathing of your Inner Fermentation closer to the breathing of a tree, and in which ways is it closer to that of a human? And in which ways is it different from both?
• What is it you breathe out into your environment during Inner Fermentation?
• What is it you breathe in from your environment during Inner Fermentation?
• Does the latter stay the same all the time? Are there stages of Inner Fermentation which require different things to breathe in?
• When will “oxygen” in your environment turn your Inner Fermentation sour? How does that look like? What does this oxygen correspond to in your processes of Inner Fermentation?

Note that there aren’t any right or wrong answers here, but only answers which are a fit for yourself and your processes. The purpose of the Homework (of all these Homeworks, for that matter) is for you to explore your own inner processes, and not to learn some facts by rote!

Hands-On Fermentation Homework: Liquid Manure

Today’s Hands-On Homework isn’t for everybody, I’m afraid. In fact, if you don’t have a garden (or have access to a garden e.g. of friends), I strongly recommend you don’t attempt to do it.

Yep, this includes people with a balcony (trust me – both you and your neighbours will bitterly regret this Homework if you attempt to do it on a balcony!).

Fear not, though! For those of you who thus can’t follow along, I’ve got an alternative listed below…

Also, today’s Homework isn’t a process of fermentation. Or rather, there is some element of fermentation involved, but the process as a whole is something different, as you’ll see (and smell) quite clearly.

In fact, I could easily have listed this Homework under a section “Fermentation Gone Wrong”… 😉 But there is something to be learned here from the access (or non-access) to oxygen, I think. Besides, I was kinda tired of all these drink recipes! 😀

So without further ado, here are the instructions for Liquid Manure, an excellent kind of home-made manure for any veggie garden, but also for flower beds, trees or shrubs (the alternative Homework for people without access to a garden follows below):

Stuff you need

What you’ll need for a stinky and plant-healthy liquid manure is

• a big bucket or other open vessel – preferably something you won’t need for other purposes anymore, as it’ll stay smelly for a good long while
• water (rainwater is great if you have it, but ordinary tap water will do)
• suitable herbs (see notes below), enough to losely fill your bucket
• a wooden stick or other device for stirring (again, something you won’t need again for other purposes)
• a stone, brick or similar, large enough to keep the floating herbs below surface and small enough to fit into your bucket (as above, not anything you need again for other stuff later
• a watering can
• an old cup, measuring cup, or similar, to ladle liquid from the bucket into your watering can (You know the drill by now: Don’t use anything you plan to use for other stuff later!)

Herbs

A classic for liquid manure are nettles. They are rich in nutrients, and very healthy for other plants. They also grow in a lot of areas, and are usually abundant and easy to identify.

Other suitable herbs include comfrey (great e.g. to fertilize tomatoes!) or common horsetail (Equisetum arvense). My suggestion would be to check gardening books or websites for your local area to find out which of your native wild plants make for suitable liquid manure – or to talk to old-time gardeners and ask them for their advice.

Of course, you can combine any of these herbs for a mixed liquid manure!

Instructions

This is really simple and easy. The biggest hurdle is the smell… 😉

1. Put your bucket somewhere where the smell won’t bother you or your neighbours, and in the shade.
2. Dump herbs in until it is filled (you can slightly press down to make them fit, but don’t press them tightly).
3. Cover with water, stir, and put the stone on top to keep the herbs from floating up.
4. Continue to stir, preferably daily. Add more water if necessary, in case too much evaporates.
5. The whole thing will bubble and foam – continue stirring.
6. Once the bubbling subsides, your liquid manure is ready to use! Ladle some into your watering can, and fill up with water (in a ratio of roughly 1 part liquid manure : 10 parts water). Water your plants with this liquid gold. 🙂 It’ll keep for a while, smell and all, i.e. you don’t have to use all of it right away!
7. Once you’re done and the bucket is empty, the remaining plant parts can go into your compost.

Some Notes on the Process

As I said, this isn’t fermentation. Or rather, some amount of fermentation might be involved, but there are quite clearly other processes dominating. Alcohol won’t develop, obviously, as there isn’t enough food for fermentation critters, and neither will acidity (I strongly recommend against taking a sip to try, though! 😀 ).

Still, there is plenty of access to oxygen all along, which influences the outcome.

There is yet another difference to your herbal wine or herbal mead, besides the sugar content and the management of oxygen, and it has a big influence on the outcome of this Homework… Can you spot it? 🙂

Alternative Homework

If you don’t have access to a garden to a. store the liquid manure while it develops, and b. to use it up, I really recommend you don’t try this Homework! (Seriously – it’s incredibly smelly. Do not attempt to do this indoors!!)

Instead, my suggestion is for you to ferment another batch of flower lemonade. This time, if at all possible, pick different flowers than before – and pay very close attention to how the lemonade develops, and how its access to oxygen influences the process.

If flowers are absolutely not available to you either at this time, either do the same for a herbal wine, or if you have any other ferments going right now, use them as part of this Homework and focus on how oxygen influences their development.

Conclusions and Outlook

Today’s essay has been very heavy on Air – and it was our first foray into the question of “Which kind of environment does a fermentative process need to thrive?”.

We’re going to explore this question even further next time, as the environment is one of the things which, quite literally, makes (or can break) your ferment – as has hopefully become clear from today’s essay.

And yep, this holds not just for Hands-On Fermentation, but also for Inner Fermentation… 😉

The next essay will go up on on Sunday, June 21st. And as usual, I’m looking forward to your thoughts, questions and comments below! 🙂

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Image: Carolina Garcia on Unsplash