The role of temperature in producing sauerkraut

Is temperature linked to the quality of your sauerkraut?

idea temerature for fermentation
what is the best temperature for fermentation?

In the short time we have been running this blog we have been asked about the optimum temperature for the fermentation process to take place. We have successfully fermented a range of foodstuffs at room temperature,  let’s say from 18oC to 22o. There is no method in this, it is simply that Maggie was brought up to leave the fermenting vegetables in the kitchen or a heated utility room. As such we’ve never been tempted to leave them in the garage or garden shed. As different types of cabbage take different amounts of time to ferment into sauerkraut, it always seemed likely that temperature is a variable in the process.

I eventually became impatient not knowing, I was also intrigued by the idea that  the quality of our own sauerkraut fermentation could be qualitatively improved by allowing it to take place at a slightly lower or higher temperature. The first two science papers I found dealing with the issue didn’t offer explicit conclusions, however third time lucky! India is one of the world’s big producers of cabbage, the spoiling of the raw cabbage before it gets to the consumer is a significant problem. So Indian interest in fermentation is something that is culturally relevant but also has commercial implications. An article in the Indian Journal of Ecology from 2017,  Effect of Temperature on Fermentation and Quality of Sauerkraut provided a lot of useful data.

In an experiment, Pran Krishna Thakur, Payel Panja and Jahangir Kabir tested the quality of sauerkraut produced at a low (15o-20o C), ambient (25o-30o C) and high (35o-40o C) temperatures. The paper is well written if you’d like to know more about yeast and bacterial profiles of sauerkraut fermentation at different temperatures follow the link. However the headline is that the sauerkraut was of a higher quality when fermented at the lower temperature (15o-20o C). This is in line with the general advice, however it’s worth noting that the experiment was undertaken with the shaan variety. I suspect that there may be some variability with different types of cabbage, but that’s a story for another day.

The Perfect Valentine’s Dinner

Show someone your love by taking an interest in their long-term health and wellbeing. Fermentation is a game changer.

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The media (traditional and social) are full of valentine news, view and suggestions. Local traders, shops and supermarkets have an overwhelming array of products linked to St Valentine’s day. However the way in which you decide to treat your loved one says a lot about you. Whilst chocolates, Champagne or roses spring immediately to mind they may by simple clichés of what people are supposed to give, rather than lasting indications of love.

Perhaps a different approach would be to offer your partner (and yourself) something likely to offer nourishment and a lasting health benefit. It is easy to overstate the qualities of naturally fermented probiotics. But we can feel confident that they are likely to make a long lasting contribution to wellbeing in a number of ways. Evidence is starting to emerge that positive gut flora, may be correlated with, stable weight, and generally improved physical and mental health across a number of measures.

Clearly probiotics are not just for February the 14th, and moving towards a healthy diet is a long term project. But talking about fermented foods or trying them for the first time, may be a great way of showing your partner that you really care, and that you want them to enjoy the best possible health. When you create fermented foods at home, not only are your own family exposed to the product, but the idea and your positive actions can influence a wide circle of friends.  Something that can’t be said of a bottle of fizz or a bunch of roses.

Whatever you do, and whoever you do it with have a great day.

Stephen and Maggie

Simple homemade sauerkraut recipe

How to make simple sauerkraut, a traditional homemade fermentation recipe, suitable for beginners, inexpensive but very healthy.

cabbage
fermented cabbage for lifelong health and wellbeing

This a very simple recipe illustrating how easy it is to to make healthy fermented foods. Sauerkraut is a perfect starting point for your first fermentation project, it is quick, low cost and will provide plenty of gut friendly bacteria. Those little friends will work for you, supporting your immune and digestive systems, helping you to feel great physically and mentally. This is based on a traditional recipe from my family, quite literally passed on from mother to daughter for generations. If you are interested in a technical explanation of how fermentation and probiotics works, and what the evidence is for the health benefits, follow the link to resources at the foot of the page.

Ingredients:

  • around 1kg cabbage (finely sliced)
  • 1 medium carrot (grated)
  • salt (unprocessed, such as sea salt, do not use table or iodised) – proportion for cabbage to salt: 1kg of cabbage to 20 grams of salt
  • 2 bay leaves
  • 4 allspice berries

Preparation:

  1. make sure everything is perfectly clean, (the containers, utensils, work surfaces, chopping boards) as you want only good bacteria to grow
  2. take off first layer of leaves from your cabbage, also remove any damaged leaves
  3. finely cut or shred it
  4. grate the carrot
  5. mix it in a big bowl
  6. add salt and massage it in until cabbage starts release its juice then leave it for about 10 min
  7. you may wish to use a wooden vegetable stomper to squeeze more juice (different names for the same tool are pounder or tamper)
  8. put 1/3 of your mixture in a ceramic pot or you can use a glass jar, just make sure it is sterilised
  9. add 1 bay leave and 2 allspice berries
  10. add another 1/3 of the cabbage
  11. add 1 bay leave and 2 allspice berries
  12. squeeze it until brine covers all of the cabbage (it needs to stay submerged throughout the fermentation process)
  13. put the pot or jar on a plate just in case it spills out of the jar, the level will rise, if you use a glass jar don’t allow the product to make contact with a metal jar lid
  14. you can use a weight to keep the cabbage immerse or even a small (clean) plate
  15. Leave for 5-6 days and voila 😉

Remember:

Do not use a metal bowl or metal utensils as they will react with salt, sorry to be a bore but everything must be clean, any harmful bacteria you introduce may taint the product. Make your first batch small, then scale up. Remember with fermented vegetables you win in many ways you get the nutritional value of the ingredients plus the probiotic benefits.

Feedback:

Please leave feedback about this or your own fermented recipe in the comments section lower down the page.

Resources:

For the science behind fermentation visit the resources page, please see our disclaimer.

Your health and microbes

What is gut health? How much does science really know. Where can you get more information from?

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The interconnected relationship between microbes and humans is an increasing object of research and general public interest. Microbial communities are all around us, on the equipment you are using now to view this article, in your home, place of study or work. Crucially microbes have a significant presence on our skin and inside our bodies, particularly in the digestive tract, with the highest concentrations found in the colon. It should be pointed out the the consumption of fermented foods is linked to a positive, increased richness in gut flora.

Over the last decade advances in technology have led to improved understanding of the collection of bacteria, fungi and archaea (single cell microorganisms) that make up the human microbiome. More importantly there are ongoing attempts to understand the relationship between an individual’s microbiome and their health and wellbeing. In scientific terms the study of the human microbiome is in its infancy, but there are already a wide range of studies linking microbes living in the human gut to health and wellbeing. Elizabeth Bik has written a journal article outlining this general area of research and its challenges and opportunities. I would recommend The Hoops, Hopes, and Hypes of Human Microbiome Research to anyone wishing to get an overview.

The Bik article was published in 2016, and reflects one perspective (albeit a particularly well informed insight). A search on Google Scholar this morning (13th February 2018) for the term  microbiome found over 20,000 entries; each entry likely to correspond to a journal article, book/book chapter, or other document. The point being, that this is a rapidly evolving area of enquiry. The types of human experience which appear to correlate with the microbiome is growing and includes; memory, obesity, depression, cancer, Crone’s disease, the immune system and much, much more. However as Elizabeth Bik points out in her article, the fact the certain microbes are correlated with a particular condition does not necessarily mean they cause it or are caused by it.

If you have a particular interest in gut health my advice is to find some good quality journalism as a starting point. If you need something more then go to the best scientific papers available. In my humble opinion, using one article or piece of research rarely builds a full enough picture. If you find out anything interesting feel free to email us or add it to the comments section below.

Gut bacteria and your health

How far should we take responsibility for what we eat?

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A conversation with a colleague and a question received by email prompts me to remind anyone reading this blog that science is limited in many respects. Scientific claims can be overstated and results can sometimes come about by chance! Our own approach is to consider all evidence on its merits but to apply our own common sense. I would urge everyone else to do the same. Any good scientist is likely to know about the limitations of their findings, and they should be highlighted in their research papers. I would hope for this to be reflected by journalists writing about science.

Part of the motivation for creating this blog is to take a bit more responsibility for my own health, and to encourage others to do the same. We can’t do without reliable high quality science, but that doesn’t mean that research published by scientists or academics  is necessarily correct, or should be taken seriously.

In my own field of psychology/contemplative science, research is a starting point and needs to be treated with a healthy scepticism. Once a particular concept has been successfully tested a number of times  (replication), only then can it start to be considered as potentially reliable. So if you read something on these pages that interests you, follow the links and check out the source material. And keep the concepts at arms’ length until you feel you can fully engage with the material. All the views expressed on this website are opinions of the contributors and or people writing about gut health. they may not reflect the views of the website owners and must be read in relation to the respective scientific research. Please read our disclaimer.

Gut bacteria and obesity; eating yourself thin

There is growing evidence that gut bacteria is linked to obesity. Preliminary experiments with mice appear to be supported by human studies.

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Ongoing research into the role of the microbiome (bacteria in the gut) in human wellbeing is at a very early stage. But the frequency of media headlines linking gut bacteria to health is growing. As with all areas of science, claims which have not been verified in clinical trials and subsequently replicated must be treated with caution. Nevertheless the evidence of a relationship between gut microbiome diversity and obesity has been repeatedly demonstrated in mice.

The microbiome is a term used to describe all of the genetic material of a microbiota, the entire range of microorganisms present in a particular context, in this case the human gut.

There have been a number of studies which show that obese mice tend to have fewer different types of gut bacteria than thin mice. The thinking is that a greater range of gut bacteria is likely to positively influence the way that the digestive system breaks down food. Having more (types of) bacteria is linked to efficient processing of what we eat, with the results of a tendency not to be obese. Recent research reported in The Independent looked at the weight gained by 1,632 female twins over nine years. The study calculated that only 41% of the weight increase could be explained by genetic factors.

On closer inspection it was estimated that becoming slimmer or maintaining the same weight was connected to the consumption of dietary fibre (typically found in whole grains, fruit and vegetables). The study also discovered that the women who had gained weight, had a lower diversity of gut bacteria. These findings were in line with similar studies with mice. Although not yet conclusive the overall evidence linking the shape of our body and the composition of our microbiome is growing.

How your food directly affects your brain

There is a two way communication system between the gut and brain, this is one way that gut microbiota mediate our health.

gut bacteria
bacteria – crucial to your health

The growing excitement over the role of gut bacteria is being fuelled, in part, by the realisation of the potential role of the gut – brain axis. The gut-brain axis is the hard wiring between the digestive tract and the brain. That is to say a direct communication link passing information between neural, hormonal and immune systems. A key point to make is that the communication is bi-directional, that means the brain talks to the gut and that the gut talks to the brain. Thus the microbiota (gut bacteria) and metaboloites (small molecules that are the product of metabolism) may be in reciprocal communication with different parts of the brain. While this has a direct and obvious impact on processes related to eating and digesting, there is rising evidence that our gut flora may be significant factors in physical and mental health.

The relationship between emotions and  the digestive system is one of which we are intuitively aware. For example, feelings of love often manifest as ‘butterflies’ in the stomach. Engaging in team sports enables you to observe pre-match nerves in both yourself and others; the digestive system often plays an obvious role in how some people deal with tension! There is evidence that stress is a mediating component in gut microbiota, perhaps through increasing or decreasing the optimal conditions for certain types of bacteria to flourish.

New studies are suggesting that individual microbiota may be influential in functions as apparently disparate as memory and fear. It is not known what the basis of the relationship is, where the causality can be found. But that there is a correlation between what is in our gut and how we experience life in terms of mental and physical well being. The take home point is that many of the things we eat and drink are able to positively and negatively influence our health. By taking more interest in what goes into your stomach you might do yourself a power of good.