Rice shinpaku structure or not?

Rice structure or not rice structure? Extending the review from last post with three more papers.

Key to sake production is the shinpaku or white opaque center. The shinpaku is generally important because of its increased ability to gelatinize during steaming, has a softer center for koji to invade once it breaks through the firmer outer layer, and is more highly convertible by the koji enzymes. All of this is true no matter the milling rate. For these reasons much of the breeding of new rice varieties has involved attempts to improve the significance of the shinpaku. However, as ginjo and daiginjo become more important types of sake, high millability is also becoming more important.

In particular, the papers analyze why some are better suited for high polishing levels while others are not. This characteristic is hugely important for ginjo and daiginjo styles of sake which have been on the rise in importance for some time now. This week I will look at three more articles on the same basic topic. However, before covering the additional papers, I would like to clear up a loose end from the last article.

The papers discussed in the last article, discussed the characteristic type of shinpaku each varietal has. These characteristic types include: non-lined (I think no-shinpaku would be a better name), lined, bellied, dotted, and ellipsoidal. As I mentioned in the article I was not sure what was meant by lined. Actually, I was thinking that it was a dense shell around the shinpaku. However, this was wrong. The lead author on the three papers, Masahiko Tamaki, sent me some nice pictures that make it clear. I don’t have permission to post the pictures so I will attempt to provide a diagram that gets the information across.

In the following diagram there are five characteristics represented with each having a side angle view of a rice kernel on the left and a cross section view looking down the long axis on the right. The first characteristic pattern, non-lined, represents rice without a significant shinpaku (white area in the center of the rice). Most eating rice has this characteristic. Next is the lined shinpaku which is the best structure for high milling levels. The bottom two bellied and ellipsoidal both have larger shinpaku but they are also more brittle. This gets in the way of milling and creates more broken rice. Dotted, is the final characteristic and is somewhere between non-lined and lined in terms of its suitability for high milling levels.

Rice kernel characteristics of shinpaku

OK, now that we have cleared up what was meant in each characteristic it is time to move on to the three additional papers. Masahiko Tamaki is the lead author for this set of papers as well. They are:

The first of these three papers looks at differences between rice kernels with shinpaku and without where the kernels are of the same variety. Two varieties (Senbon nishiki, Yamada nishiki) were analyzed each of which were grown in three different areas of Hiroshima (Shobara, Takamiya, Miwa).

The hardness of the center of each type kernel was measured with no significant difference between the three plots but quite significant difference between the shinpaku and non-shinpaku kernels within the same type. Other locations, four more, were also tested with similar results. In addition, starch characteristics were analyzed finding again, no significant difference between the shinpaku and non-shinpaku kernels. Given all this the conclusion continues to be that the differences in the structure of endosperm cells are responsible for all the properties of the shinpaku.

The second paper looks closer at the differences in hardness of the rice kernel and its shinpaku and their likelihood of breakage. They considered four types of rice: Kairyo omachi, Hattan nishiki No. 1, Senbon nishiki and Yamada nishiki. The first two of these have a significant higher breakage rate as compared to the second two. Very cool pictures taken with a Scanning Electron Microscope (SEM) show that Yamada and Senbon nishiki have much more tightly packed starch than does Kairyo Omachi and Hattan nishiki. This tight packing makes the rice harder and less susceptible to breakage.

Paper three analyzes the same rice varieties as paper two but compares starch properties rather than hardness. This study suggests that the shinpaku tissue may also play a part as well as the temperature of the early ripening period. This is, of course, in addition to the endosperm structure’s demonstrated impact on millability.

Digging into US rice – where did it come from?

Digging into US rice – where did it come from?

Discussions with a friend challenged my understanding of some aspects of US rice production. I had focused on California rice for most of my earlier research and really, if the truth is to be known, discounted most of the rest of the country. My understandings were not all wrong but some generalizations where flat out incorrect and this led to other beliefs being wrong as well.

Most of the rice grown in California is medium grain while most of the rest of the country grows predominantly long grain rice. This fact led to my incorrect conclusion that most of the country grows Indica rice; NOT TRUE. As it turns out very little of the rice grown in the US is actually Indica rice. So, what is all this long grain rice that is being grown? It is tropical Japonica; sometimes known as Javanica. I prefer to use Javanica but this term is becoming less and less common. Anyway, tropical Japonica comes in both long and medium grain forms.

So, while being wrong about most states growing Indica, it is true that there is a distinct difference between the rice grown in most rice producing states and California. Most rice grown in California is Japonica while most rice grown in the other major rice producing states is tropical Japonica; a distinctly different rice. Even the medium grain rice grown in these states tends to be tropical Japonica.

Continue reading “Digging into US rice – where did it come from?”

Rice Malt, Not for Sake but still interesting

Rice Malt, Not for Sake but still interesting

While researching rice and enzymes I came across an article on how steep time and temperature influence rice malt enzyme production. Malting is a major part of most beer brewing but while sake is, by some definitions, a beer, it does not use malt; not rice malt, not any kind of malt. Instead the rice used for sake is milled to remove the outer layers of the grain, which destroys all possibility of malting.

Malting is the process of transforming a grain from a seed to a malt that contains not only the starches and proteins that where present in the seed but also enzymes that can be used to convert the starches and proteins in the malt to sugars and amino acids.

To malt seed, the seed is steeped in water and allowed to dry a little in order to awaken the seed to begin to grow. The steeping and drying may be carried out several times to fully engage the embryo’s growth but ensure the seed does not drown. Once the embryo has begun to sprout roots and a shoot, a maltster will halt the embryo’s transformation by heating or kilning the grain. This prevents the enzymes from fully distributing throughout the endosperm and converting it before it is ready to be used.

Continue reading “Rice Malt, Not for Sake but still interesting”

Preparing Your Rice for Sake Brewing

This article discusses the process of preparing rice for brewing sake or making koji.

An important step performed several times during the sake brewing process is the preparation of the rice. We prepare rice for the moto, then again for each step of the san-dan-jikomi, the three step addition of rice, koji and water to build up to the moromi or the main fermentation. Another addition is sometimes done new the end of moromi called yodan. The preparation of the rice is the same for each of these additions.

Rice preparation consists of washing, rinsing, soaking, draining, packing, steaming, cooling and finally adding it to the brew. Rice for koji also goes through the same process except rather than adding it to the brew it is inoculated and then incubated. But this will be covered in another article. Let’s cover each of these steps separately. Continue reading “Preparing Your Rice for Sake Brewing”

Intro to rice, sake rice – where do we start?

This article gives a brief history of the rice that is important to sake brewers from the beginning to present (10,000BC to now).

OK, so what about rice? Isn’t it all the same? Well, I guess there is brown rice and white rice. Isn’t this all there is to it? No, it’s not, there’s much more. While we are interested in sake rice, I will cover some basic background, history and such to build a foundation we can use to better understand rice, its differences, and what is important for making sake.

The scientific name for the species we call rice is Oryza sativa. Within this species are three subspecies: japonica (short grained rice), indica (long grained rice) and javanica (a medium grained rice). Javanica is now known as tropical japonica. While japonica seems to imply that it originates in Japan, this is not the case. In fact, it appears that its origin is China. Continue reading “Intro to rice, sake rice – where do we start?”

Sake Yeast Mash – The Moto

This article looks at the three types of Sake yeast mashes, also known as moto and shubo. The differences between these three moto are examined.

Moto (元), Shubo (酒母), Yeast mash are all names for the Sake yeast starter. In this article I will only use the term “moto” but the three can be used interchangeably. Moto is where the number of yeast cells is increased to the needed level. The moto is used to inoculate the main sake fermentation, the Moromi (諸味). To build the moto we start with rice (米), koji (麹) and yeast (酵母). These three ingredients along with water were the only ones used for moto originally. The method to produce this original moto is known as Kimoto. It features a vigorous mixing, taking many hours, to produce a puree of the ingredients. It was thought this vigorous mixing, called Yama-Oroshi, was needed for the ingredients to properly work together.

In 1909 a modification to the Kimoto method was developed. The modification was to drop the vigorous mixing. As it turned out, the mixing was not really needed. The modified process was called Yama-Oroshi haishi moto or Yamahai moto for short. Continue reading “Sake Yeast Mash – The Moto”

Sake basic ingredients

Sake has four basic ingredients: rice, koji, yeast and water. Each play an important part in producing the taste, aroma and appearance. Each are discussed and how they come together to form the sake we love.

Sake is made with four ingredients: rice, koji, yeast and water. All, except the koji, are familiar to most people. Koji is a mold culture grown on rice in the case of Sake. The mold is Aspergillus oryzae. It forms a white fluffy coating over the rice and excretes alpha-amylase which converts the rice starch into sugar. This is the primary function of koji in brewing sake; to provide enough alpha-amylase to convert most of the starch provided by the rice to sugar. Other compounds produced by the koji contribute to the final taste.

Once the koji converts the starches from the rice to sugar, yeast converts the sugars to alcohol. Beyond this major contribution the yeast also produces other compounds that contribute to the final taste and aroma of the sake. These two processes, conversion of starch to sugar and conversion of sugar to alcohol, proceed at the same time which allows the yeast to produce higher levels of alcohol than is the case in beer and wine. This is not to say that beers and wines can not ferment to the high levels that sake does but that special processes, outside the norm are needed to obtain the same high level normally reached with sake. Continue reading “Sake basic ingredients”