Mechanism of Umeshu and Japanese Fruit Wine-2


Umeshu, plum wine and other Japanese fruit wine are easy to make. If you understand how they work, you can make more delicious plum wine without making mistakes.


Wine but NOT Wine

Japanese Umeshu or Kajitsushu is called fruit wine in English. However, its mechanism is quite different from that of normal wine.

Normal wine uses fermentation by yeast. On the other hand, Umeshu or Japanese fruit wine is simply made by soaking fruit and sugar in liquor.

It is very easy to describe in writing. And when you actually make it, it is very easy. However, something very profound is happening. Let’s take a scientific look at how it works.

Actors are Fruit, Liquor, and Sugar

The process of making Umeshu or fruit wine is very simple. Simply put the fruit, icing sugar, and alcohol in a clean bottle and let it mature, that’s it.

Only three actors play roles in the story of Umeshu: the fruit, the liquor, and the sugar. And the story of how umeshu is pickled is made up of three parts.

The part I was the encounter between fruit and liquor.

Part II: The Diffusion of Rock Sugar

When you start making fruit wine, the first thing that happens is that the fruit and the liquor meet. What does the rock sugar do in the meantime? Actually, the rock sugar is slowly dissolving into the liquor. And the concentration of the sugar is gradually increasing.

In a nutshell, what is happening to the rock sugar is that it is dissolving into the liquor and gradually diffusing. Let’s take a closer look at this as well.

The key words here are dissolution and diffusion.

Sugar Dissolves in Liquor

Have you ever observed rock sugar in umeshu? You can see that the rock sugar is gradually getting smaller and smaller.

Rock sugar is made up of sugar particles, molecules. Each molecule is so small that we cannot see it with the naked eye. However, when many of them are gathered together, they form a large lump and become visible rock sugar.

In fruit wine, the sugar and the wine come into contact with each other. The rock sugar gradually dissolves from the surface into the liquor. Each molecule is very small and connected to water molecules. Therefore, after the sugar has dissolved, it is invisible and cannot be filtered through a colander. This is what we mean by sugar dissolving in liquor.

Sugar Diffuses into Liquor

How does sugar dissolved in liquor move? When the solution is left to stand, the concentration becomes uniform. This is the phenomenon of diffusion, which we discussed in Part I.

Sugar particles dissolved in the liquor slowly spread throughout the liquor over time. This is what we mean by sugar diffusing into the liquor.

When fruit wine is being soaked, the bottom of the bottle appears hazy. That is where the sugar concentration is very high. This is because the sugar has dissolved in the liquor, but has not yet diffused throughout.

What Happened to the Rock Sugar

Now let’s summarize what happened to the rock sugar. When you start making the fruit wine, the rock sugar slowly dissolves into the wine. It then diffuses throughout the liquor.

Plums and Fruits Float

In the process of increasing the concentration of sugar, a significant change in appearance also occurs. Plums and fruits float to the surface.

The more the sugar dissolves, the greater the density of the liquor. As the sugar dissolves in the liquor, at some point it becomes bigger than the density of the fruit. This is why plums and other fruits float.

Part 3: Fruit Meets Sugar

Let’s look at what happens a little while after you start pickling umeshu or fruit wine. At this point, the liquor has osmosis into the plums and other fruits. And the rock sugar is gradually dissolving and diffusing.

As the sugar diffuses, the concentration of sugar in the liquor gradually becomes more concentrated. Eventually, the concentration of sugar in the liquor becomes thicker than the concentration of sugar in the fruit. Then the liquor and water permeate through the fruit.

In a nutshell, this is liquor permeates through the fruit. Let’s take a closer look.

The key words this time are concentration and osmosis.

The Sugar Concentration Increases

In Part II, I wrote that sugar molecules diffuse. In other words, the concentration of sugar increases. I also mentioned in Part I that fruits also contain sugar.

From the start of pickling to a certain point in time, the concentration in the fruit is higher. During this period, the liquor osmosis the fruit, as we saw in Part I. Or we could say that it is sufficiently osmotic to reach a state of equilibrium. But that is complicated and will not be discussed here

As the sugar molecules diffuse, at a certain moment, the sugar concentration in the liquor becomes higher. This is the state in which solutions of different concentrations (liquor and fruit) are touching each other across a semipermeable membrane (cell membrane). In other words, osmosis occurs.

Osmosis Between Fruit and Sugar Dissolved Liquor

So far, alcohol and water osmosis from the liquor to the fruit occured. It’s because the concentration of sugar was higher in the fruit. This time, the concentration of sugar is higher in the liquor. In other words, alcohol and water permeate from the inside of the fruit to the outside, liquor.

Plums and Fruits Sink

Here again, a major change occurs that is visually noticeable. The floating plums and fruits sink again.

As mentioned in Part I, a lot of liquor has permeated into the plums and fruits, causing them to swell up. The sugar then draws out the liquor from the fruit. As a result, at some point the density of the fruit becomes greater than the density of the sugar-dissolved liquor. As a result, the plums and fruit sink.

The Mechanism of Umeshu is the Liquor Going In and Out

These are the principles of plum wine pickling and the mechanics of what is happening in the process of fruit wine pickling. In a nutshell, we can see that it is a very simple mechanism: liquor goes in and out of the fruit.

However, this mechanism alone does not tell us at what stage and how Umeshu becomes tasty. What kind of mechanism makes umeshu and fruit wine delicious?
What is Important for Making Tasty Umeshu - Only One Tip
Let's check what is the key to making umeshu delicious and how it works. There is only one point; shaking.


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