Aroma during koji production

Aroma during koji production

Today as I am making a test batch of koji that I am working on as a new offering (Special Ginjo Koji-kin), I am led to thinking about the aroma of the growing koji. What is that smell? Where does it come from? Well it seems that the answer, at least at the level I can discuss here, is not that complicated.

The aroma of a fresh batch of koji is often described as being chestnut like. This aroma was noticeable during my check of the growing koji at 20 hours into the process, not strong but definitely there. As the time goes by the aroma is strengthening. I am not sure if I would equate the smell of koji with chestnuts but I find the smell nice and even comforting. So what is making this aroma?

It seems that the aroma is coming from a combination of phenylacetaldehyde, 1-octen-3-ol and 1-octen-3-one. Production of phenylacetaldehyde seems to stop at around 40 hours into the process while the production of 1-octen-3-ol and 1-octen-3-one continue and can even double their concentration during the final stages of koji production (hours 44-50). However, as 1-octen-3-ol and 1-octen-3-one concentrations overwhelm those of phenylacetaldehyde a more mushroom like aroma becomes noticeable. Individually phenylacetaldehyde and 1-octen-3-one have a rose like and a mushroom like aroma respectively. Continue reading “Aroma during koji production”

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.

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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.

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Honjozo – multiple beginnings

Honjozo – multiple beginnings

While most of us who have paid attention to honjozo have heard about how the rice shortage around World War II sparked the need to stretch rice farther. For sake, this need was addressed with the addition of alcohol to produce more sake for the given amount of rice used. The most common sake in Japan, Sanzoshu (三増酒) and to a lesser extent Futsushu (普通酒), retain their use of high addition levels of alcohol. San (三) means three so Sanzoshu is triple sake. It has this name because enough alcohol is added when making Sanzoshu to triple the resultant quantity of sake. When tripling the output in this way other factors are thrown out of balance. To correct this, acids (酸類) and sweeteners (糖類) are added to sanzoshu to make it taste more like sake that has not been diluted so much.

Futsu (普通), means ordinary or standard. Despite this name, futsushu actually has a lower yearly production level than sanzoshu. And, while futsushu is not allowed to add sweeteners nor as much alcohol as is allowed for sanzoshu it is not as restrictive as special designation sakes like honjozo (本醸造). In addition to higher levels of alcohol, futsushu, as with sanzoshu, is allowed to add acids to the sake that are not allowed in the special designated class.

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A moto before kimoto? – Bodaisen to Bodaimoto

A moto before kimoto? – Bodaisen to Bodaimoto

Before getting with this article I would like to urge you to consider donating to help Japan in this time of tragedy. Three outstanding organizations which will ensure your donations will be used well are:

https://www.sakesamurai.jp/donation.html

https://www.mercycorps.org/

https://www.redcross.org/

OK, back to the article:

We often here about the three types of moto or seed mash. There is the currently most used moto type, sokujo-moto, the next most common, Yamahai-moto and the moto which was king before that, kimoto. But, before these there was another type of moto, one that was used as late as 1925 under the name Mizumoto. This moto was bodai-moto and was developed by the monks at the Bodaisen Shoreki Ji Buddhist temple.

The monks studied the techniques used in both Japan and China. They developed their method some time in or before the 14th century. A brewing  diary, “Goshu no Nikki,” describes the two step method and later starting in 1478 as chronicled by the “Tamon-in Nikki” the three step method was developed and used.  Taken together these describe how the method for making Bodaisen had transformed from a single mash sake brewing to one that used a starter culture from previous good mashes to one with a purpose made starter mash, bodai-moto, added to the main ferment and the progressions from including two and then three additions to the moromi.

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Koji production – what are we trying to do?

Koji production – what are we trying to do?

OK, so what exactly are we trying to do when making koji? Well, to examine this we need to consider the role koji plays in Sake Brewing. In sake brewing we use koji to provide a wide variety of products. These include products that provide flavor and aroma elements as well as enzymes which degrade proteins and starches into smaller component parts. For example proteins are disassembled into peptides and amino acids while starches are converted into smaller starches, dextrins and sugars.

Rice starts out with 7% to 8% protein, but much of this is milled away, so we do not focus on koji’s production of enzymes to break down this protein. Rice starch is our main focus and needs to be broken down as effectively as possible into sugars. Koji produces alpha, beta and gama amylase. Depending on how we culture the koji, we can emphasize protein or starch degrading enzymes. High temperature cultivation, 98°F to 110°F, lead to the production of saccharification enzymes whereas lower temperature cultivation, from 98°F down to 68°F, emphasizes protein degrading enzymes. So to make good koji for sake brewing we must culture the koji at high temperatures.

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To foam or not to foam, that is a question of the yeast?

To foam or not to foam, that is a question of the yeast?

Sake brewers have long used the appearance of the foam to tell the stages of the moromi’s progress (fermentation progress). The named stages are as follows:

Foam StageEnglish TranslationAprox. Timing
suji-awa (筋泡)Muscle Foamday 2-3 of Moromi
mizu-awa (水泡)Water Foam
iwa-awa (岩泡)Rock Foam
taka-awa (高泡)High FoamDay ~10 of Moromi
ochi-awa (落泡)Falling Foam
tama-awa (玉泡)Ball Foam
ji (地)Land or Ground

Pictures for each of these stages as seen through the foam can be seen at the Daishichi’s site.

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Steeping to hit the numbers

Steeping to hit the numbers

Picture the toji presiding with a stopwatch over kurabito as they steep rice for a batch of daiginjo; 28.29.30.31 pull it out of the water. A 31 second steeping to reach the desired 29% uptake of water into the rice kernels. The precision required is just amazing, but why, why is this so time critical?

We need to back up a little and consider what we are trying to do. The goal is to have our steamed rice weigh 1.38x to 1.4x the pre-steeped rice.1 That is to have the rice take up slightly less than 40% of its weight in water by the time it has completed steaming. Steaming will add another 10% or so water uptake. Backing off to pre-steam levels gives us 1.28x to 1.3x for steeping. So how long will this take and why is it different for different grades of sake?

While there are differences between rice variety and milling rates, it turns out that one of the main contributors to the rate of water uptake during steeping relates to the moisture content the rice starts with. In fact it is this factor that is the main cause for highly polished rice to absorb water so quickly and hence the need for a stop watch.

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  1. These targets may vary a bit from place to place.

How much sake does a pound of rice make?

How much sake does a pound of rice make?

I recently saw a section in “The Niigata Sake Book” labeled “How Much Sake Is Made out of 1 kg (2.2 lb.) of Rice” and thought this would make a nice topic to cover. I may later do a more in depth look at this but for now we will just get a good idea of the basics.

OK, so if we start with rice, water and some microorganisms how much sake will we get?   Well, let’s start with brown rice as does “The Niigata Sake Book.”  To make sake starting with brown rice the first thing that needs to be done is to polish the rice to a level needed for the type of sake we wish to make. To get down to the edge of junmai ginjo type sake we need to polish the rice to 60% or less. So let’s say we will mill the rice down to 60% of the original brown rice. That is, if we start with 1 lb. of brown rice this will leave us with 0.6 lbs. of white rice.

Now, for this there is a key ratio that needs to be understood. While this ratio will change somewhat for individual sakes, we will simply choose a reasonable example ratio for this analysis. The ratio of water used to the weight of rice added is around 1.3x, so that is what we will use. This implies the water needed for the fermenting mash will be 0.78 lbs. = 0.6 lbs x 1.3. The fermenting mash (the Moromi) will then be 1.38 lbs. = 0.6 lbs. rice + 0.78 lbs. water.

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Amazake – it ain’t sake

Amazake – it ain’t sake

I have meant to post a little something about anazake for some time but I keep putting it off. Now that I have gotten a question about how to make it I can see that it is overdue and I should get my act together. Amazake is a rice and koji mixture that is most thought of as a drink but has other uses as well.

OK, so to make amazake you need koji and rice. You can make koji with the method discussed in the earlier post, “Making Koji for Sake.” In this case you will need to start with koji-kin. If you prefer you can skip making your own and just buy the koji. I have both koji and koji-kin in the store.

Once you have the ingredients, koji and rice, cook 3 cups of rice just as you would to eat the rice.  When cooked, thoroughly mix 1 cup koji with the now 3 cups of cooked rice. Leave this in a warm area (75F-85F is good but could be as high as 140F) for between 6 hours and 12 hours. You should stir this every couple of hours; each time tasting it. It should get sweeter and sweeter until it stabilizes. When it stops getting sweeter it is done. At this point it should be quite mush like. Put it in a sauce pan and boil it for 5 minutes but be careful not to scorch it. This denatures the enzymes and stops the transformation. Continue reading “Amazake – it ain’t sake”