Milk Kefir FAQ | Milk Kefir Grains 101

Introduction 

Welcome to our FAQ on everything to do with milk kefir grains! Our article aims to provide in-depth, but easy-to-understand answers to everything regarding milk kefir grains. If you don't already have kefir grains, our live organic milk kefir grains can be purchased here. They are posted freshly fed and live.

What are Milk Kefir Grains?

Milk kefir grains are a symbiotic colony of yeast, lactic-acid bacteria, and acetic acid bacteria that ferment milk into a drink known as milk kefir (1). The physical bulk of the grains is mostly composed of natural polysaccharides and protein matrices produced by these microbes (1).

Milk Kefir Grains are Typically:

• White or light-yellow in colour
• Gelatinous, slimy, and elastic in texture
  Shaped irregularly
• 2 mm to 3 cm in size

Under optimal conditions, kefir grains will grow and double in volume approximately every 10 days; the individual grains themselves will grow in size until a certain point, where they’ll then divide into smaller grains. Lastly, despite being called grains, they are in no way related to grains from plants, with the word instead referring to their shape and abundance.

Where Do Milk Kefir Grains Come From? 

All kefir grains sold and shared today were likely grown from descendants of the very first kefir grains. They likely formed naturally after raw milk was continuously added and then emptied from animal-skin bottles in the Caucasus, Tibetan or Mongolian mountains (2).

Exactly when kefir grains spontaneously formed is unknown, as it predated written records, but traces of milk kefir grains have been found in tombs of the Xiaohe region in China, dating back 3500 years (3).

In 1908, kefir grains were obtained from the tribes of the Northern Caucasus by the Russian Physicians’ Society, where they then gained popularity within Russia (4). The story behind how the grains were acquired is fascinating, but parts of it have likely been romanticised. Later, they spread in popularity across the Western world in the 1960s (5).

What Should Milk Kefir Grains Look Like (Shape, Size, and Texture)?

Milk kefir grains vary in shape, size, and texture:

• Some grains may be as small as rice, sticky, and irregularly shaped.
• Others may be as large as cherries, smooth, and round

These variations result from differences in microbial composition, milk type, straining methods, and environmental conditions. You can read more about this below. Picture of various-sized milk kefir grains from the same mother batch.

What Factors Affect Kefir Grain Size, Texture, & Shape?

Origin/Strain

The microbial compositions of kefir grains influence how the natural polysaccharides and the protein matrix that make up the grains are formed. As a result, kefir grains of different strains/origins can have slightly differing baseline textures, shapes, and sizes.

Straining Technique

• Straining roughly with a metal spoon and a metal strainer will break the grains apart into smaller grains
• Gentle straining with plastic equipment won’t break apart the grains, allowing them to grow larger.

Milk Type

• Full-cream milk supports optimal growth.
• Low-fat or skim milk slows growth.
  • A slower growth rate means that the same individual grains will be exposed to more straining time, resulting in smaller grain sizes.
• Plant milk can cause grain shrinkage or death if used long-term without refreshing the grains in dairy milk.

Kefir grains also adapt to their food source, changing in both smell and texture. For example, kefir grains fed with almond milk will begin to take on a slight almond smell and soft beige colour, grow more slowly or completely stop growing, and lose their sticky coating.

Temperature

A higher fermentation temperature, such as during summer, can encourage the grains to divide more frequently. Inversely, a lower fermentation temperature will encourage the grains to divide less frequently and instead increase in size.

When grains are exposed to a temperature of over 28°C (85°F) for a few days, they can begin to take on a mushy texture: this is a sign that they are beginning to become damaged. Extended periods of this, or higher temperatures, can cause them to break down even further into an unusable liquid. Low temperatures will slow down the activity of the grains and stop them from fermenting the milk.

Does Kefir Grain Size Matter?

There is a common myth that smaller kefir grains are of a low quality – this a myth, but there are some differences between large and small grains. Firstly, using small kefir grains will result in a faster fermentation. This is because the grains have a higher surface-to-mass ratio compared to that of larger grains, as per the square-cube law.

This increased surface area allows for the yeast and bacteria residing in the grains to colonise and ferment the milk more quickly. However, allowing your kefir grains to grow large enough to the point where there is a distinct and clear difference almost needs to be intentional through delicate straining techniques and fermentations carried out at around 18°C (65°F), which supports large grain growth over division.

Although some people do have a cosmetic preference for larger grains. In some cases, it may also make straining easier, as once the grains grow sufficiently large, they can be scooped out with a fork instead of straining them out with a sieve.

Can Milk Kefir Grains be Eaten?

Yes, you can eat milk kefir grains, and there are even health benefits to it. Milk kefir grains are composed of:

• Probiotics – from live bacteria and yeast that are beneficial to the gut when consumed
• Kefiran – a polysaccharide matrix that has been studied for its potential anti-inflammatory, antimicrobial, and immune-modulating effects
• Protein – an essential building block for the body and has a role in supporting immune function.

Can Milk Kefir Grains Die?

Yes, kefir grains can die if they are not looked after. But don’t worry, it is easy to keep your grains in tip-top shape by keeping the following in mind:

Temperature

Milk kefir grains are generally happy between 18°C - 28°C (65°F - 85°F) (6). Occasional swings above this range is well tolerated by kefir grains. But extremes in heat, or prolonged periods above this range, can begin to damage them.

Milk kefir grains can still ferment at very low temperatures, such as at 4°C (39°F), in a fridge – fermentation just takes a week instead of 1-2 days. Prolonged periods of fermentation at this temperature range shouldn’t kill the grains, but it can cause them to become sluggish in activity, though.

Feeding Times

Neglect is one of the most common reasons kefir grains die. Milk kefir grains should be fed regularly to keep them in a healthy state, just like a pet. Ensure that you feed them every 24 to 48 hours, and if you’re keeping them in the fridge for storage/a break, feed the grains once every 2 weeks at a minimum, but preferably once a week.

Refreshes With Animal Milk When Using Plant Milk

Many people will use their milk kefir grains to ferment plant milk, such as coconut milk, almond milk, oat milk, etc. This is a perfectly acceptable and fun way to vary your consumption of milk kefir, or to avoid dairy. However, these other options lack the essential nutrients that the grains need to survive and thrive. You should refresh your kefir grains with animal milk every few batches to keep them happy.

Are Kefir Grains Reusable?

Yes, kefir grains are reusable! If you take care of your kefir grains, you’ll only ever have to buy them once, and you’ll even grow extra for your friends and family over time. Follow our organic milk kefir grain instructions here to make a delicious milk kefir that will also support the health and growth of your kefir grains.

Are Kefir Grains Safe?

Yes, kefir grains are not only safe for the vast majority of the population, but they are also packed with probiotics and are a great way to make milk kefir at home that is cheaper and more probiotic than store-bought milk kefir. With that being said, homemade milk kefir does need to be made in a hygienic environment with grains that are healthy and free from contamination. Potential signs of grains that are not healthy include signs of mould, disintegration, strange colouring and smells, or if they produce milk kefir that smells or tastes off as well. In such cases, you should discard grains and milk kefir to be safe.

When milk kefir is consumed in high quantities or initially by someone introducing it to their diet, there can also be side effects such as bloating, gas, and mild stomach discomfort – but these symptoms usually subside once they have been introduced and incorporated into a diet. If you do have any special considerations, such as recent surgery, you should consult with your doctor prior to consuming milk kefir.

Where Can I Buy Milk Kefir Grains?

Here in Australia, live milk kefir grains cannot be found in stores like Coles and Woolworths, and the vast majority of health food stores. This is also the case worldwide, as kefir grains are a live culture that needs to be attended to; so, they’re normally only available through specialised sellers.

Grains can be sourced locally, but quality, proper handling, and support given can vary greatly. This is where we come in. For over half a decade, we have been selling high-quality, organic milk kefir grains all across Australia, from major cities such as Perth, Melbourne, Sydney, and Brisbane to all smaller regional areas through the internet. Every order comes with high-quality kefir grains, instructions, and expert email support (if needed), to help you have the best experience possible when entering the world of fermentation.

Are Milk Kefir Grains Vegan?

No, milk kefir grains are not vegan, but they can be used to make plant-based milk kefir. While the lactic acid bacteria and yeast within kefir grains are inherently vegan, they are grown and fed on dairy. Furthermore, the two major components of the actual grains themselves – kefiran, the polysaccharide matrix, and protein- come from dairy.

However, milk kefir grains can be used to make plant-based milk kefir by fermenting a wide range of plant milks, such as almond, soy, oat, coconut, cashew, rice, and pea milk.

Do note that there may still be traces of dairy from the kefir grains within these plant-based milks, and that the grains themselves are still a derivative of an animal product. Lastly, the grains will need to be refreshed with dairy milk every few batches as it contains essential nutrients for the kefir grains' survival. So, it cannot be said that plant-based milk kefir is truly vegan, but for many non-strict vegans out there, it may as well be.

What Can I Do With Excess Milk Kefir Grains?

If you have extra healthy milk kefir grains that you don’t know what to do with, there are a number of options to choose from. You can:

• Give the extras to your friends and family
• Consume them yourself
• Feed it to your dog
• Compost or bin them

How Quickly Do Milk Kefir Grains Grow?

Milk kefir grains will roughly double in volume every 2 weeks under ideal conditions, so don’t be concerned if you can’t see them multiplying from batch to batch, unlike water kefir grains which have a significantly higher growth rate. If your grains are growing notably slower than this or aren’t growing at all, it’s likely due to one or more of the reasons below.

Why Aren’t My Milk Kefir Grains Growing?

Here is a full, comprehensive list of why kefir grains may not grow. Sometimes a small tweak is all that’s needed to get the grains growing again, but in other cases, the only option is to source new kefir grains if they have been overally damaged and don’t appear to recover.

Ambient Temperature Is Too Low or Too High

An ambient temperature that is too high or too low can negatively affect the growth rate of your kefir grains. The optimum temperature for fermentation is 23°C (75°F) – about room temperature. However, anything in the range of 18°C - 28°C (65°F - 85°F) is acceptable (6). Temperatures below this range can cause the kefir grains to become sluggish in growth, whereas temperatures above this range can start to kill the kefir grains.

Overcrowding

As the kefir grains grow over time, more milk needs to be added to each batch, or some of the grains should be discarded. Aim for a ratio of 1 teaspoon of kefir grains to 1 cup of milk. If you don’t do this, over-fermentation and overcrowding can occur, which will slow down the growth of your grains or even damage them.

Infrequent Feedings

Ensuring that the grains are fed on a frequent and consistent basis promotes growth. Fermenting for more than 48 hours in particular has a detrimental effect on the kefir grains, as the grains' extended time in contact with the acidic milk kefir can damage the microflora within them.

Type of Milk

Milk kefir grains will nearly always grow best in full-cream, organic cow's milk, goat’s milk, or sheep milk. The grains will grow a bit slower in lite and skim milk, but it’s still a perfectly okay choice. Milk kefir grains won’t grow at all in plant milk and lactose-free milk.

Over-Fermentation

When over-fermentation occurs, the milk kefir that the grains are in can become very acidic and start damaging the kefir grains.

What Is the Difference Between Milk Kefir Grains and Water Kefir Grains?

Despite both being called kefir grains and sharing many similarities, they are quite different to each other at the end of the day. Below is a comparison of the similarities and differences between these two amazing cultures.

Similarities

Symbiotic Cultures

• They are both symbiotic colonies of yeast and bacteria (SCOBYs) that contain lactic acid bacteria, acetic acid bacteria, and yeast (1).

Health Benefits

• Both grains produce a drink with potential health benefits that can support immune function, digestion, and the gut (2). 

Reusable

• When the grains are healthy and in an optimum environment, they are reusable and grow with each successive batch.

Feeding Times

• Both grain types should be fed a fresh source of food every 24 to 48 hours.

Temperature

• A temperature range of approximately 18°C - 28°C (65°F - 85°F) is most comfortable for both grain types, and they’ll begin to struggle or even potentially die outside of these ranges (6).

Differences

Appearance & Texture

• Water Kefir Grains: Semi-translucent, colour can range from dark brown to clear. The grains are firm, slightly squishy, and brittle—easily broken apart under pressure.
• Milk Kefir Grains: White or slightly yellow, opaque, and coated in a sticky white gel. The grains are squishy and elastic, and cannot easily be broken apart.

Growth Rate

• Water Kefir Grains: Growth is highly variable—can double in volume every few days or sometimes not grow at all. Very sensitive to conditions.
• Milk Kefir Grains: Grow more slowly, usually doubling in volume about every 10 days under optimal conditions. However, they are more robust and generally keep growing even under poor conditions, unlike water kefir grains.

Food Type

• Water Kefir Grains: Feed most easily on sucrose (cane sugar), but can also use other sugars such as fructose. Molasses can be added to supply extra trace minerals. Source
• Milk Kefir Grains: Feed mainly on lactose (milk sugar), but also use milk proteins and fat. They can adapt to plant-based milk or ferment sugar solutions.

Cross Compatibility

• Water Kefir Grains: Cannot be used to ferment milk or make milk kefir.
• Milk Kefir Grains: Can sometimes be converted to ferment sugar water and make water kefir, although there are caveats to this process.

End Product Taste

• Water Kefir: Slightly sweet, tangy, fizzy, and light in taste.
• Milk Kefir: Sweet, sour, tangy, slightly thick, and fizzy.

Probiotic Range & Quantity

• Water Kefir Grains: Contains a lower quantity and diversity of probiotics.
  • Species Diversity: ~16 species of live microbes (probiotics) (7).
  • Probiotics (CFU) Count: ~125 million to 35 billion CFU per cup (8).
• Milk Kefir Grains: Contains a higher quantity and a more diverse range of probiotics.
  • Species Diversity: ~24 to 56 species of live microbes (probiotics) (9).
  • Probiotics (CFU) Count: ~27.5 billion to 278 billion CFU per cup (1)(10).

Vegan Friendly?

• Water Kefir: Yes, water kefir is completely vegan.
• Milk Kefir: Not vegan unless made with plant-based milk.

Can I Use Milk Kefir Grains to Make Water Kefir?

The answer is yes, you can technically use milk kefir grains to make water kefir grains by converting them to ‘water kefir grains.’ This is done by repeatedly leaving milk kefir grains in sugar water for 3 days for about 7 successive batches (more on this in the question below). After 3 weeks, they should be mostly converted if all went well and begin to produce water kefir.

By feeding milk kefir grains with only cane sugar (sucrose), many of the lactose, fat, and protein-loving microbes in the kefir grains will die off; but some will adapt and break down sucrose instead, eventually leading to a water kefir–like population of bacteria and yeast.

However, you may be better off buying water kefir grains instead of doing a conversion, as:

• There’s a high chance of failure in converting the grains – they can very easily die, even when everything is done correctly
• It’ll take a lot of time
• The adapted grains likely won’t grow or will grow very slowly and are
• The end product will taste slightly different to water kefir made from true water kefir grains

Because of these downsides, it’s easier and better to buy water kefir grains, which also have the following benefits:

• Already adapted to fermenting sugar water
• Ferment without a high chance of failure
• Will grow and multiply easily
• Produce a great-tasting and consistent water kefir

How Do I Convert Milk Kefir Grains to Water Kefir Grains?

As said above, it is possible to convert milk kefir grains to water kefir, although there are some caveats. If you'd still like to give it a go, despite the downsides, here’s how to convert milk kefir grains to make 1 cup of water kefir every 24 to 48 hours:

Equipment and Ingredients

• 2 tablespoons of fresh milk kefir grains
• 1 tablespoon of cane sugar
• ½ teaspoon of molasses
• 1 cup of chlorine-free water (boil and cool or use filtered water)
• A glass jar with a lid
• A measuring jug
• Fine mesh sieve(metal is okay)

Steps

1. Rinse your milk kefir grains with cold or room temperature, chlorine-free water to remove all milk residue
2. Fill a jar with 1 cup of cold or room temperature, chlorine-free water
3. Add the molasses and sugar, stirring until dissolved
4. Add the kefir grains to the jar and place the lid on lightly, allowing air to escape
5. Ferment at room temperature and out of direct sunlight for 3 days
6. Strain the kefir grains with the sieve, discarding the liquid
7. Repeat steps 2-6, 6 more times, stopping on day 21

Note: It is normal for the kefir grains to change to a brown colour during this process

You are now ready to follow our water kefir instructions and recipes for 1 tbsp of water kefir grains if all went well – otherwise, the grains have been lost and need to be discarded. Signs that the conversion failed include that the kefir grains:

• Disintegrated
• Grew mould
• Took on a strange colour or smell
• Do not ferment the sugar water after following the water kefir instructions and recipes

Can I Use Water Kefir Grains to Make Milk Kefir?

No, you unfortunately cannot make water kefir with milk kefir grains. While it may sound counterintuitive that you can convert milk kefir grains to make water kefir, not vice versa, it does make sense once you look deeper.

This is because milk kefir is far more complex than water kefir, as it contains fats, proteins, and lactose (milk sugar), while water kefir only contains sucrose (cane sugar). As a result of this complexity, milk kefir contains a wider range of microbes, some of which can handle the sucrose found in water kefir. While many of the microbes in kefir grains will die off, such as those well-adapted to feeding on lactose, fat, and protein, some microbes will adapt to breaking down sucrose instead, converting the milk kefir grains into grains that can ferment and make water kefir.

On the other hand, the microbes found in water kefir grains aren’t as diverse in range as those of milk kefir grains, and they are only adapted to converting sucrose. The microbes found in water kefir grains can’t digest lactose and aren’t adapted to dealing with milk’s proteins and fats. While there may be some strains of bacteria or yeast that can adapt, it is just too much change for the majority of those microbes.

You can think of it like a land animal trying to go swimming, vs a sea creature trying to go on land; the milk kefir grains can adapt, but it's too much for the water kefir grains. To be clear, this has not been studied and proven scientifically, as we were unable to find much on this topic – but it is our best evidence-based theory on why this is the case. 

How Can I Make Milk Kefir Grains at Home/From Scratch?

Unfortunately, milk kefir grains cannot be made from scratch and instead need to be sourced from someone who already has them, such as from specialised sellers like ourselves. This is because all kefir grains sold and shared today are likely grown from descendants of the very first kefir grains. These grains likely originated thousands of years ago by accident, when milk was continuously added and then emptied from animal-skin bottles in the Caucasus, Tibetan or Mongolian mountains (2).

While we know the conditions and environment in which they likely formed, the exact conditions are unknown; we have not been able to find any credible reports of someone creating them from scratch. It could be that the perfect conditions, wild microbes, and length of time haven’t been found yet. But if you’re simply wanting to make milk kefir at home, instead of engaging in years of lengthy experiments that may or may not be successful, it’s probably easier just to source some grains.

How Do I Use Milk Kefir Grains?

That’s a great question! Please view our milk kefir grain instructions and recipes to learn how. These beginner-friendly instructions have been written by us, based on our years of expertise and experience.