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Home Brew Sake

June 20th, 2010 at 6:05 pm

Final Steps in Sake Brewing

After moromi is complete we have only a few more steps to go in our process. These are: secondary ferment, racking, fining, pasteurization, amelioration and bottling. Conditioning and maturation are also terms for the secondary ferment. For the most part the secondary ferment begins after the sake has been pressed out of the lees. At this stage the sake can be anywhere from milky white to relatively clear. However, in all but unusual cases, more, finer lees will settle to the bottom as the sake completes its ferment and rests.

As the ferment completes, alcohol production ceases but the yeast are still active. During the early stages acetylaldehyde, diacetyl and esters are produced and cleaned up, however the clean up follows production by a good amount of time so when there is no more alcohol to produce there is still a sizable amount of these compounds remaining. At this stage the yeast complete their work and clean up remaining levels. It is also at this time that the sake flavors start to come together for a more integrated taste.

Once the lees have settled as much as they are going to it is time to rack the sake to a newly sanitized conditioning container. A fining agent, like bentonite, can be used to help pull the particulates out of solution and fall to the bottom. In general it will be about 10 days for the lees to drop. Racking can be done ether by decanting or by siphoning. It is easier to siphon from one secondary container to the next without mixing in the very light sediment from the bottom than it is to decant without mixing the sediments.

As long as the sake is kept at 45-50F the racking process can be repeated several times, with each time removing more of the particulates and leaving a clearer sake. However, with each time some sake is also lost. During one of the rackings, the sake should be pasteurized.

To pasteurize, place the freshly racked sake in a water bath while monitoring the temperature of the sake. Once the sake temperature reaches 140F take it out of the water bath. This is a pretty gentle pasteurization. As the sake heats up, CO2 is driven off. This can look like it is boiling but it is only the CO2 coming out of solution.

At this point there are only amelioration and bottling left. Amelioration, for those who choose to do it is similar to the method used for wine and consists of adding a sugar solution (sake sugar syrup) to lower the SMV value to the desired range. Unless the ferment is stopped early, which can result in unwanted by products of the ferment remaining, or a yodan addition is made, the sake will have a SMV as high as +12 to +16. Most like sake with no more than an SMV of +10; even this is pretty dry sake.  To lower the SMV by one point for one US Gallon it takes 0.23oz. of sucrose (table sugar).  Once the SMV is where you want it and you are happy with the taste, it is time for the final step, bottling.

To bottle, rack the sake into its final resting place; these should be freshly sanitized bottles that can be filled to limit the amount of air space in the bottle. Place the filled bottles in a water bath as before and bring the sake to 140F. Once it reaches 140F take the bottle out of the water bath and put the lid on. As the sake cools a slight vacuum will form which will help to keep the bottle sealed.

Walla!

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10
  • SakeNewbie
    6:56 pm on September 8th, 2010 1

    Wow thanks for the info and pasturizing and bottling! Great info.

  • Humbert
    6:40 am on February 6th, 2015 2

    Hi Will,
    I have some doubts about the water addition phormula you mention in your book, on page 163. What do you refer for VolumeG and Volume.
    Thanks so much,

  • Will
    8:27 pm on February 6th, 2015 3

    Humbert,

    There is a typo there on page 163. Both VolumeG and Volume are the same variable; the initial volume of the sake in gallons.

    water addition = ((VolumeG * Current_ABV)/Target_ABM) – VolumeG

    Where:
    – VolumeG is the initial volume of sake
    – Current_ABV is the Alcohol By Volume of the sake
    – Target_ABM is the desired or target Alcohol By Volume for the sake after water addition

    Current amount of alcohol in the sake = (VolumeG * Current_ABV)

    final volume required = Current_alcohol / target_ABV

    addition = Final_volume_required – VolumeG

    Does this make it more clear?

    Thanks,

    Will

  • Humbert
    7:58 am on February 10th, 2015 4

    thanks Will!It s 100% clear.
    I have some doubts regarding to know when the rice is ready:
    1) Water uptake: I get easily 70% wáter uptake, is that correct? maybe I am weighting it incorrectly…
    2) when do you know the rice has drained properly?
    3) what do you recommend a rice with 18% amylose or 23% amylose?

    thanks,

  • Will
    9:13 pm on February 23rd, 2015 5

    Humbert,

    1) How are you calculating 70%?
    2) When it stops dripping it has drained enough.
    3) 18% amylose is the correct ball park for good sake rice.

    Thanks,

    Will

  • Humbert
    1:58 am on February 24th, 2015 6

    Hi,
    1) weighing the rice after 1 hour soaking.
    2) fantastic
    3) I was getting the same conclusion, rice with 23% amylose don’t get gelatinize very well.
    thanks!

  • George
    9:38 pm on July 15th, 2015 7

    Hi Will! Thank you for your book and the videos. Those combined with your recipe have me off to what I hope is a good start.On day 31 I added 7.5 cups of vodka to make honjozo. After several tastes I can smell and taste sake, but both are affected, but not overwhelmed, by the vodka. Tomorrow,July 16th, is the 44th day so I’ll be racking to secondary jugs and want to add water to each gallon jug to reduce the ABV from about 24%. My first hydrometer reading was 0.995 and everything else is going so well that I’m afraid I’ll mess it up. When do you think I should do the addition? I’ll use your formula to compute the amount to add.
    Thank you for your help!

  • Will
    1:10 pm on July 19th, 2015 8

    George, Hi,

    I would add the water once you are satisfied with the clarity of the sake. About the same time you pasteurize, assuming you do. Let us know how it all turns out.

    Thanks,
    Will

  • JD
    7:08 pm on January 2nd, 2018 9

    Hi, just wondering why the first pasteurization step(before the final rack) is necessary. is it just because it takes so long for the solids to fall out of suspension and flavor stability is a problem? Would cold crashing the sake once the yeast has done it’s clean up work be better? It seems like it should speed up clarification, slow down any microbial issues and avoid extra pasteurization(which I assume is a plus). Thanks

  • Will
    5:35 pm on January 4th, 2018 10

    Hey JD,
    It is not necessary it’s traditional. Many sakes are made with a single pasteurization or none. However, each of these has an effect on flavor as well as killing bugs, denaturing enzymes and such. Two pasteurizations will, all things being equal, be more stable and have a more traditional taste. There are many different variations that you might like to try; the number of pasteurizations, pasteurization temperature or time and so on. Pasteurization is not closely related to clarity.
    Thanks,
    Will

 

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