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Merge pull request #17 from ControlledMold/Minor-edits-throughout
Minor edits throughout
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_posts/2020-10-10-temperature-water-content-and-polishing-effects-on-koji.md

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@@ -118,6 +118,6 @@ Rice polishing ratio, explained by [Nada-ken](http://www.nada-ken.com/main/en/in
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#### References
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Murakami Hideya. Koji Studies - 6th edition. Chapter 5 - Koji Enzymes. The Brewing Society of Japan: Tokyo, 1986.
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Murakami Hideya. Koji Studies - 6th edition. Chapter 5 - Koji Enzymes. The Brewing Society of Japan: Tokyo, 2018.
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Naoto Okazaki et al. Effects of koji-making conditions on growth and enzyme production. Journal of The Brewing Society of Japan, 74:10 (1979), 683-686, https://doi.org/10.6013/jbrewsocjapan1915.74.683

_posts/2020-12-16-the-koji-making-process-temperature-mycelium-and-moisture.md

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@@ -194,7 +194,7 @@ Here is a list of Japanese terms pertaining to the koji-making process. This can
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#### References
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1. Murakami Hideya. Koji Studies - 6th edition. The Brewing Society of Japan: Tokyo, 1986.
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1. Murakami Hideya. Koji Studies - 6th edition. The Brewing Society of Japan: Tokyo, 2018.
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2. Katsuya Gomi, Regulatory mechanisms for amylolytic gene expression in the koji mold Aspergillus oryzae. Bioscience, Biotechnology, and Biochemistry 83:8 (2019), 1385-1401, https://doi.org/10.1080/09168451.2019.1625265
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3. Shigetoshi Sudo et al., Factors in the formation of haze. Journal of The Brewing Society of Japan, 97:5 (2002), 369-376, https://doi.org/10.6013/jbrewsocjapan1988.97.369
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4. Kazunari Ito et al., Quantitative evaluation of *haze* formation of *koji* and progression of internal *haze* by drying of *koji* during *koji* making. Journal of Bioscience and Bioengineering, 124:1 (2017), 62-70, https://doi.org/10.1016/j.jbiosc.2017.02.011

_posts/2021-06-04-flavourzyme-a-purified-enzyme-mixture-from-a-oryzae.md

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6. Flavourzyme 500MG Product Data Sheet - Novozymes A/S. Dated 2017-08-24. Accessed 2021-06-06 from: https://www.ibric.org/myboard/view.php?Board=scicafe000352&filename=0003423_1.pdf&id=3423&fidx=1.
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7. *Koji Studies*, 6th ed.; Hideya, M.; The Brewing Society of Japan: Tokyo, 1986.
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7. *Koji Studies*, 6th ed.; Hideya, M.; The Brewing Society of Japan: Tokyo, 2018.
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8. Mochizuki, T. About the use of enzymes in miso brewing. *Journal of the Brewing Society of Japan* **1969**, *64* (5), 423–430. https://doi.org/10.6013/jbrewsocjapan1915.64.423.

_posts/2021-09-07-design-of-the-koji-room-koji-muro.md

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@@ -51,7 +51,7 @@ That being said, these koji rooms were effective - and even though they lack mos
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## Modern Koji Rooms
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Modern koji rooms solved all the problems with old koji-rooms, and starting in the 1950s, all breweries quickly renovated to employ the following design features, which I'll quickly summarize:
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Modern koji-rooms solved all the problems with old koji-rooms, and starting in the 1950s, all breweries quickly renovated to employ the following design features, which I'll quickly summarize:
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1. Electric heaters (often wall-mounted panel heaters or wall-mounted heating coils)
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2. Modern insulation (fibreglass, mineral wool, PVC foam, styrofoam, or polyurethane foam)
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**Table 1 - Design parameters for common koji substrates [4]**
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{:.table-clean}
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| Substrate | Initial Moisture<br /> (%) | Initial Specific Volume<br /> (L/kg) | Peak Heat Generation <br />(kJ/kg-dry/h) | Total Heat Generation<br /> (kJ/kg-dry) |
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| -------------------------------------- | -------------------------: | -----------------------------------: | ---------------------------------------: | ---------------------------------------: |
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| Wheat bran & rice husk koji (1:1) | 50-55 | 9.2 | 158 | 1990-2620 |
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Let's demonstrate which of these three design criteria is our limit, using our example.
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First, consider the requirements for **heat removal**. We can show that our 300kg of rice-koji at *hiki-komi* has a dry weight of 195kg, and will generate 1623W at the peak of its metabolism (see Appendix - [Step 4](#step-4---determine-the-ventilation-requirements-for-heat-removal)). Our conductive heat losses were calculated to be 764W, so we know that ventilation for heat removal must equal 859W by exchanging indoor air with cold, outdoor air. This requires a ventilation rate of 41m³/h.
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First, consider the requirements for **heat removal**. We can show that our 300kg of rice-koji at *hiki-komi* has a dry weight of 195kg, and will generate 1623W at the peak of its metabolism (see Appendix - [Step 4](#step-4---determine-the-ventilation-requirements-for-heat-removal)). Our conductive heat losses were calculated to be 764W, so we know that ventilation for heat removal must equal 859W by exchanging indoor air with cold, outdoor air. This requires a ventilation rate of **41m³/h**.
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![Heat balance of the koji room with ventilation sized for heat removal](/assets/images/koji_room/02kojiroomheat.png)
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#### Air shooter
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A common way to transfer steamed substrate into the koji room, and finished koji out of the room, is to use a device called an *air shooter*. This is a a Japanese *wasei-eigo* term for what would commonly be called a pneumatic conveying system consisting of: 1) a blower 2) a feed assembly consisting of a hopper, rotary valve, and solids-conveying educator, 3) a bunch of hose, and 4) an outlet cyclone (optional). These are much faster than transferring substrate by hand.
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A common way to transfer steamed substrate into the koji room, and finished koji out of the room, is to use a device called an *air shooter*. This is a Japanese *wasei-eigo* term for what would commonly be called a pneumatic conveying system consisting of: 1) a blower 2) a feed assembly consisting of a hopper, rotary valve, and solids-conveying educator, 3) a bunch of hose, and 4) an outlet cyclone (optional). These are much faster than transferring substrate by hand.
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![](/assets/images/koji_room/Airshooter.png){:height="550" .center}
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*Top: a schematic of an air-shooter (pneumatic conveying system), bottom-left: feed assembly, bottom-right: blower. From [1] and Toyo Shokai Co., Ltd.*
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#### Step 2 - Determine the koji amount, dry weight, and room dimensions.
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The weight of steamed rice at inoculation (hiki-komi) will be 300kg. If the unsoaked white rice has a moisture of 13%, and the water absorption ratio at inoculation is 34%, the actual water content of the koji is:
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$$
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\%Total\ moisture = \frac{Total\ Water}{Total\ Weight}=\frac{13\%+34\%}{100\%+34\%} = 35.1\%
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$$
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This is in agreement with Table 1. Thus the dry weight of the steamed rice is 194.8kg and its peak heat generation is 5843kJ/h or 1623W (unit conversions not shown).
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Let the depth of koji be 5cm. Based on Table 1, 300kg of steamed rice will occupy approximately 660L or 0.66m³ in volume and require a table with an area of 13.2 square meters (geometric calculations not shown). Let's select a 5.3m x 2.5m table. To allow for clearance and the storage of other items, let's select a room of 8m (L) x 5m (W). Finally, a ceiling height of 2.0-2.2m is standard - we will select 2.2m (H).
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- $RSI_n$ = insulation R value (metric RSI value), equivalent to x/k (m-K/W)
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Select a 4-inch polyurethane insulation with a total metric RSI value of 4.24 (m-K/W). We'll use a convective heat transfer coefficient of 8.0 W/m-K on both sides of the wall. Now, we can find the overall heat transfer coefficient:
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$$
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\frac{1}{U} = \frac{1}{8}+4.24 +\frac{1}{8} \text{ (SI Units)}\\
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U = 1.3W/m^2\cdot K
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$$
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As well as the heat losses through the wall:
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$$
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Q = (1.3W/m^2\cdot K)(137.2m^2 )(30^\circ C-5^\circ C) \\
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Q = 764W
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$$
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Heat flux is simply heat transfer divided by area, or Q/A. In 1-D steady state heat transfer, this term is constant no matter where you are along the wall.
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$$
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\frac{Q}{A} = h(T_1 - T_w)
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$T_w$ is the temperature at the koji room wall
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If we solve for the wall temperature:
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$$
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763W = (8W/m^2\cdot K)(137.2m^2)(30^\circ C-T_w)\\
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T_w = 29.3^\circ C
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$$
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This is well above the dew point of our koji room, so no condensation is expected.
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----
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#### Step 4 - Determine the ventilation requirements for heat removal
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This is a heat balance on the koji room:
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$$
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Q_{koji} = Q_{wall} + Q_{vent}
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$$
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- $Q_{koji}$ - peat heat generation from koji (W)
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- $Q_{wall}$ - heat losses through the wall (W) (from Step 3)
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Heat removed by ventilation is simply flow rate times the difference in the air enthalpy in and out of the system:
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Q_{vent} = \dot{m}(H_1 -H_2)
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$$
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Where,
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- ṁ = mass flow rate of air (kg dry air/s)
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\text{Water generated by koji} = \text{Water removed by ventilation}\\
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- F = fraction of heat generated by koji removed by evaporative cooling (0.8)
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Our mass balance becomes:
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$$
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\frac{(0.8)(1623W)}{2429.8J/g} = \dot{m}(18.8\text{g water/kg dry air} - 2.7\text{g water/kg dry air})\\
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We know its specific volume is 0.885 m³/kg dry air so the ventilation rate is 105.7m³/h (indoor basis).
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----
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$$
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\begin{align}
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& C_6H_{12}O_6+6O_2 \rightarrow 6CO_2 +6H_2O+2872kJ/\text{mol} \cdot \text{glucose} \\
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& 2872kJ/\text{mol}\ \text{glucose} \times\frac{1 \text{mol}\ \text{glucose}}{6\text{mol} \ CO_2}= 478.7kJ/\text{mol}\ CO_2 \rightarrow0.00209\text{mol}\ CO_2 /kJ\\
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& 2872kJ/\text{mol}\ \text{glucose} \times\frac{1 \text{mol}\ \text{glucose}}{6\text{mol} \ CO_2}= 478.7kJ/\text{mol}\ CO_2 \rightarrow0.00209\text{mol}\ CO_2 /kJ \\
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& \frac{0.00209\text{mol}\ CO_2 }{kJ}\times \frac{5843kJ}{h}(Q_{koji})=12.2\text{mol}\ CO_2 /h
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\end{align}
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We can convert to volumetric CO₂ generation using the ideal gas law:
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\dot{V}_{CO_2,koji}=\frac{\dot{n}RT}{P}\\
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\dot{V}_{CO_2,koji} =12.2\text{mol}\ CO_2 /h\times\frac{(8.314J\text{mol}^{-1}K^{-1})(303.15K)}{101300Pa}\\
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\dot{V}_{CO_2,koji} =12.2\text{mol}\ CO_2 /h\times\frac{(8.314J\text{mol}^{-1}K^{-1})(303.15K)}{101300Pa} \\
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CO_2 \text{ generated by koji} = CO_2 \text{ removed by ventilation} \\
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Our mass balance becomes:
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#### Step 7 - Determine the heating requirements
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Heat balance on the koji room:
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Our heat balance becomes:
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1623W + Q_{heater} =763W + (0.03317kg\ \text{dry air}/s)(78.3kJ/kg - 11.78kJ/kg)\cdot(\frac{1000W}{kJ/s}) \\
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Q_{heater} = 1621W
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$$
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