Pasteurization(火入れ) and Suda-san

Yesterday, we bottled a new batch of sake, a Junmai-shu, and while some of  will be sold as nama (unpasteurized), some of the bottles were destined for pasteurization and storage over the summer to mature. Today, Suda-san (in the photo) and I therefore set about the task of pasteurizing about 350 bottles (1.8L) of sake which involves heating up the sake to 65C for about 15 min using hot water.

Pasteurizing sake for peace

As you can see from Suda-san’s expression, placing and removing fairly heavy 8-bottle cartons of sake  in and out of hot water is quite fun. The other method used to pasteurize sake here involves running the sake through coiled tubing in a large tank containing hot water, which is then bottled.  For higher quality sake, bottles are heated individually, for regular sake, it’s the tube.  And that’s the story of pasteurization at the brewery.

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4 Responses to “Pasteurization(火入れ) and Suda-san”


  1. 1 Will Auld January 16, 2010 at 04:14

    Greg,

    Interesting. I am continually looking to understand the differences between the process the pros are following and that of the home brewer of sake. I pasteurize at 60C. I bring the temperature of the sake up to 60C and remove it from the heat. Your going to 65C for 15 minutes. That is quite a difference. Given your school degree will you comment on this difference?

    As a separate question, here I am thinking of the moto, in the yamahai moto, does the low pH from the lactic acid kill off the wild yeast and bacteria, including, eventually, the lactobacillus itself? Or does it just slow them down so they do less harm and maybe some good?

    Thanks

    • 2 gjnewton January 16, 2010 at 09:19

      Dear Will,
      concerning the pasteurization, I was perhaps a little too general as I was in a rush and very tired, so I will give the specific details here.
      The unit in the above picture contains hot water (the heat source, steam, is at the far end) but is separated into 8 sections by baffles (you can see the handles). The sake is gradually brought up to a final temp of 65C, at which point it is removed immediately. However, it is in the hot water for about 20 min in total. It enters from one end, and gradually moves along, increasing in temp as it goes along. So really, it is likely not that different from your method, except for the final temp. At 60C, almost all bacteria will be killed, so that is likely not a problem. In the lab we use 121C to kill everything, but that temp is would not be so kind to sake.
      As for the moto, the addition of lactic acid creates an environment which is not inducible to rapid growth by the other bacteria that are present, but they are likely not killed, just not happy.

      greg

  2. 3 Timothy Sullivan January 16, 2010 at 22:09

    Hi Greg,
    what is the approx temperature of the water as it enters this pasteurization process? is it already quite warm? or room temperature?
    Thanks!
    Timothy

    • 4 gjnewton January 17, 2010 at 12:27

      Timothy,

      The water is quite warm- I would guess between 45-55C. The baffles separate the compartments from the heated end, which is close to 70C, but not completely, resulting in a temp gradient.

      thanks for your interest,
      greg


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