Lievito Madre, Beer, anerobic and aerobic environments
I've made beer, wine, and sourdough bread, and it has always struck me how similar the process is for all three. They all rely on single-celled fungi and, to a lesser degree, bacteria.
When brewing, your nemesis is Acetobacterial fermentation, which converts alcohol into the decidedly acidic acetic acid. To prevent your wine or beer from turning into vinegar, we use airlocks, which create an anaerobic environment that Acetobacteria don't like.
Before we start, there are two things you need to know about yeast.
#1. In order to reproduce and multiply, it needs Oxygen.
#2. If there is no Oxygen, Yeast doesn't die; it simply changes gears and starts producing CO2 and alcohol.
As we learned above, Acetobacteria LOVE alcohol and quickly turn it into Acetic Acid (vinegar); the only way to prevent this is to keep Oxygen away from the Acetobacteria.
This brings me to Lievito Madre and why we might want to incorporate some of the procedures used to make it into our sourdough startup routine.
Part of every Lievito Madre routine involves either submersing the dough in water or tightly wrapping it. Both of these measures keep oxygen away from any alcohol-loving Acetobacteria that might be lurking in the dough, leaving only the anaerobic-loving Lactobacteria around to help acidify the dough.
The end result is a yeast rich dough with some happy lactobacteria.
I have some feedback on your thoughts here. Let me know if interested...
Of course, not sure why you would ask. If I am mistaken I’m happy to stand corrected.
Ah, a breath of fresh air, thank you.
My trepidation exits since the last time I gave feedback on decisive statements I somehow became the the bad guy.
I only care to share the truth (or facts as far as can be known)…
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Some good points however...
#1 - that isn't actually true. Yeast do grow under anaerobiosis. Evidenced by an increase in biomass. From experience I have emptied out the bottom of large hectolitre tanks with a shovel to remove dead yeasts and tartrates. Yet they were only inoculated with a small packet.
#2 - Yeasts may do well to utilise oxygen, however in sugar rich environments they prefer fermentation despite it yielding less energy. The reason can be explained as a means to deter competition. Producing alcohol from sugars can impede other less alcohol tolerant microbes.
Lievito Madre.
The common methods, Piemontese (submerged in water) and Milanese (wrapped and bound) are actually quite opposing in terms of oxygen exposure.
Only the Milanese method which uses wrapping and binding is truly anaerobic while the Piemontese method where dough is initially submerged in water actually promotes oxygenation since the dough rises and floats to the surface and is exposed to the air.
Comparing this to wine fermenting, the piemontese method is akin to red wine making (open top tanks) compared to white wine making (airlocked tank) Milanese anaerobic method.
I’m confused. the few times I’ve made red wine (I home brew in my basement) the one time I let the airlock dry out I wound up with vinegar. Are you talking about the initial fermentation? Making beer and wine I have encouraged an oxygen rich environment for the first day or so.
I would point out that until the dough has fermented enough to float, it is in an anerobic environment, and even then only the top is exposed to the air.
Of course, yeast continues to multiply in an anaerobic environment, sugars have plenty of O2, just a little harder to access.
I am also curious about your thoughts on the premise that LM techniques reduce Acetic acid formation in favor of lactic acid.
I have done experiments using vacuum packed starter that seem to support my theory.
I enjoy having my positions challenged, so long as both sides remain respectful and in search of the truth there can be no valid reason for offense.
open top tanks for red wine wine making. This is normal in wine making, it helps with colour extraction primarily (search: pump over; delestage). Completely anaerobic red wine making likely leads to a light coloured red wine and reductive flavours.
While alcoholic fermentation is occurring it's not really possible for AAB (acetic acid bacteria) to take hold (CO2 production creates an anaerobic environment). Yeast may produce VA (volatile acidity - acetic acid and acetaldehyde) in the initial stages of red wine fermentation however.
The Piemontese method of Lievito Madre maintenance is designed to promote oxygenation. Typically the dough will remain submerge for only 60 minutes or less of its 12 or more hours duration. To suggest this is done to promote an anaerobic environment is completely inaccurate. Morandin a proponent of the technique goes so far as to describe the oxygenation properties of the water the dough is surrounded by.
"I am also curious about your thoughts on the premise that LM techniques reduce Acetic acid formation in favor of lactic acid."
Not sure what you are referring to here. The differing overnight fermentation techniques, Piemontese and Milanese do different things while both help to prevent an increases in TTA in the dough. But the approaches are quite different.
The binding method helps to supress a build up of acids by augmenting it with dissolved CO2 released by the yeasts. While the Piemonte method allows the developing acidity to be released into the surrounding water.
Indeed of course, although from experience some people have a hard time having their truth questioned, glad to know you're okay with that...
While a much longer timeframe than what you are doing with your dough, when pickling vegetables ( I also ferment veggies from my garden), they need to be submerged to maintain an anaerobic environment. My conclusion concerning the Piemonte method was based on my experience making pickles. sauerkraut and Kimchi.
In the case of Pickles, for example, Pickles that might get exposed to the air can be "ruined," while those that remain below the surface are fine. From what I've read about the Piemonte method, the soggy outer part is not what is used to perpetuate the starter.
My previous experimentation with Anaerobic fermentation of a sourdough starter used a very dense 2 parts flour 1 part water mix instead of the typical 1:1 ratio. The relatively dry starter was an idea I stole from some of the Lievito Madre methods I had read about.
What got me started on this thought process was the remarkably active starters that are produced using the different LM methods. Since the methods are different but produce similar end results, I thought It might be useful to determine what commonalities they have that produce such phenomenal results.
As you suggested I researched delestage fermentation.
"During fermentation, yeast produce carbon dioxide, this carbon dioxide causes grape solids to rise creating what is referred to as a cap. The cap can present a number of risks, a combination of acetic bacteria, the warmth of fermentation and oxygen could easily convert a vat to vinegar. For this reason, winemakers must manage the cap. Cap management also forms part of the winemakers desired stylistic preference."
It sounds like the grape skin cap is acting as an airlock for the wine.
You've misunderstood, delestage is a technique employed during wine making that is done typically by pumping over the wine also referred to as rack and return, this done to promote oxygenation and submerge the cap. Sometimes the pump valve may opened to pull in air to further promote oxygenation.
Cap management is very important in red wine making, as the text you quoted describes. A static cap is much more risky in open top tanks as is the norm with red wine making. Typically the cap will be punched down or pumped over every 8 hours or so. A more involved process compared to white wine making at this fermentative stage.
No you wouldn't want to have the cap act as an airlock hence the need for cap management.
I always wondered why red wines had sulfites. Can't imagine they would taste good in bread.
All wine contains sulphites even if not added, since yeast can produce some and red wine generally contains lower levels compared to white wine.
The bulk of the phenolics that come from the skins and seeds offer strong antioxidant capacity, while white wine made without the skins / seeds is far more suspectable to oxidation and typically incurs a higher addition of sulphite during processing.
Sulphites finds application in baked goods such as biscuits (cookies) for example. Being a powerful antioxidant it can be used as reducing agent.
Baked products, will bake off any occurring molecular SO2, bound sulphites will remain however.
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You are absolutely correct.
Michael is making some important points here. It helps my overall understanding of what is happening when a particular environmental factor is changed for the LM.
Also, in my experience and as I have learned from others, rolling the LM into a coil is in part an opportunity for more oxygen to persist inside the LM during that feeding cycle, helping yeast development.
Yeast needs dissolved oxygen to start growing and multiplying (aerobic phase) but once there are sufficient yeast cells the yeasts switch over to an anaerobic (no oxygen needed) “fermentation” stage to convert carbohydrates into carbon dioxide and alcohol.
At the point where you are mixing and rolling the dough, you are indeed adding the necessary 02 for the initial multiplication and growth of your starter yeast. However, once the dough is submerged (as in lacto fermentation) you are depriving the dough of 02 - to push the yeast into a fermentive state.
The lack of oxygen and the production of both alcohol and CO2 work together to inhibit bacteria.
Kombucha has the scobi, delestage fermentation has its cap, and Beer makers have their airlocks. All of these processes start with an oxygen-rich environment, then prevent additional oxygenation to facilitate fermentation.
I would propose that the dough that floats to the top, prevents O2 from reaching the rest of the dough, allowing it to ferment.
Acetic Acid Bacteria in wine making.
I started this post.
I was fascinated by the complex procedures for Lievito Madre.
Seeing the similarities to Lacto-fermentation, I thought, what a clever way to reduce Acetobacteria and encourage yeast growth and fermentation.
The sourdough that I was using at the time produced a very sour loaf, so I experimented:
I refreshed it 3 times in a vacuum-packed bag with low hydration.
As I have mentioned elsewhere, the bag inflated with CO2, and had a slight alcoholic smell.
The dough produced a very mild bread that rose faster than it had with the previous refreshment.
Since the steps were inspired by the LM method I started this post.
An interesting aside reducing AA over LA might not be the best outcome as discussed here:
https://www.sciencedirect.com/science/article/abs/pii/S0168160521001276