JPH0143547B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method and apparatus for brewing vinegar that can efficiently produce high-quality vinegar in a short period of time. Conventionally, various methods have been known for brewing vinegar, one of which is known as a static fermentation method. According to this method, submerged aeration stirring fermentation method, etc.
It has the advantage of producing brewed vinegar of superior quality compared to other methods, but it requires a long period of time for fermentation and the fermentation takes place over a wide flat surface (surface), resulting in a low yield of acetic acid per unit area. Moreover, since the fermentation is carried out in an open system, alcohol, acetic acid, etc. in the moromi undergo large evaporation and escape, and acetic acid, that is, vinegar, cannot be obtained with a high yield. Therefore, the present inventor conducted various researches in order to eliminate the above drawbacks while retaining the advantages of the static fermentation method. As a result, the inventors of the present invention vertically attached a porous carrier film on which acetic acid bacteria were attached in a closed fermentation tank. Vinegar moromi is supplied to the upper part of the carrier membrane and permeated into the carrier membrane to flow down the carrier membrane and come into contact with the acetic acid bacteria, and the oxygen concentration in the gas phase is adjusted to 5 to 60% (V/
I learned that high quality vinegar can be obtained in a very short period of time and with good yield by carrying out acetic acid fermentation while maintaining the oxygen concentration at V) (hereinafter, oxygen concentration is expressed as V/V). The present invention was completed based on this knowledge. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in more detail below by showing one example of the apparatus of the present invention with reference to the accompanying drawings, and further showing a method of brewing vinegar using the apparatus. FIG. 1 shows a longitudinal schematic explanatory diagram showing one specific example of the vinegar brewing apparatus of the present invention, in which 1 is a box-shaped closed fermentation tank, inside of which is a carrier film on which acetic acid bacteria have grown. A large number of 2 are arranged vertically. Further, above the carrier membrane, there is provided a means for supplying and permeating the vinegar mash into the upper part of the carrier membrane. As for its structure, as shown in the figure, a fermentation tank 3 is provided above the fermentation tank, and a through groove 4 or a through hole that closely fits the upper end of the carrier film is provided in the bottom wall of the tank, and a through hole 4 is provided in the bottom wall of the fermentation tank. The upper end of the carrier film 2 may be brought into close contact with the groove or hole to close the groove or hole, the moromi is supplied from the moromi supply pipe 5 to the mortar retention tank 3, and the upper end of the carrier film 2 is immersed in the vinegar mortar, or a mortar dispersion pipe or the like may be used. Examples of the method include dropping or injecting vinegar moromi onto the top of the carrier film using a container (not shown). The method of immersing the upper end of the carrier membrane in the vinegar moromi is preferable because the vinegar mortar can be supplied to the carrier membrane without considering the permeation rate of the vinegar mortar into the carrier membrane. Reference numeral 6 denotes an air supply pipe, one end of which communicates with the gas phase of the fermentation tank, and the other end connected via an on-off valve 7 such as a solenoid valve.
It communicates with an oxygen supply source 8 such as an air supply pump or an oxygen cylinder. Reference numeral 9 denotes an oxygen concentration detection element provided in the gas phase section of the fermentation tank, and the detection element 9 and the on-off valve 7 interposed in the air supply pipe 6 are connected via the oxygen concentration control device 10. The control device 10 is configured so that the oxygen concentration in the gas phase is always within a specific range. The oxygen concentration in the gas phase measured by the oxygen concentration detection element 9 is converted into an electrical output by the oxygen concentration control device 10, and this output opens and closes the on-off valve 7 to control the gas phase. The oxygen concentration is configured to be automatically adjusted. The means for controlling the oxygen concentration in the gas phase of the fermentation tank of the present invention is comprised of the above-mentioned air supply pipe 6, oxygen concentration detection element 9, and oxygen concentration control device 10. Reference numeral 11 denotes a moromi tank, which temporarily stores the moromi that is leached and dripped from the lower end of the carrier membrane. 12 is a moromi circulation pipe, and a circulation pump 13 is interposed in the middle thereof. One end thereof communicates with the inside of the moromi tank 11, and the other end communicates with the moromi supply pipe 5. 14 is a temperature measuring body such as a thermometer inserted into the mortar,
The temperature control device 15 is connected to the control unit 17 (in this example, a hot/cold water flow on/off valve) of the heat exchanger 16 provided in the mortar circulation pipe 12, and the moromi flows through the carrier membrane and is converted into acetic acid. The structure is such that the moromi is kept at an appropriate temperature for fermentation by the acetic acid bacteria when it comes into contact with the bacteria. 18 is a gas phase circulation pipe that causes convection in the gas phase between the carrier membranes, makes the oxygen concentration in the gas phase uniform, supplies sufficient oxygen to the carrier membrane, and removes the fermentation heat generated in the carrier membrane. A carrier membrane is provided to maintain a constant temperature at all times. and,
At least two arbitrary locations in the gas phase portion of the fermentation tank (in this embodiment, two locations on both ends of the top wall of the lid of the fermentation tank) are communicated, and a gas circulation device 19 is installed in the middle.
and a temperature control device 20. And 2
Reference numeral 1 denotes a temperature measuring device such as a thermometer, and the temperature adjusting device 20 is configured integrally with the temperature measuring device or via a temperature controlling device 22 provided separately as shown in the figure.
It is configured to be able to control the temperature of the gas phase by communicating with a control unit 23 such as a hot/cold water flow on/off valve. A huge amount of fermentation heat is generated on the surface of many carrier membranes during acetic acid fermentation, but since the carrier membrane has a large surface area, the fermentation heat is effectively released into the gas phase. Fermentation heat can be effectively removed by a temperature control device in the gas phase circulation pipe. The two temperature control devices 16 and 20 described above may be used when it is necessary to control the temperature of the moromi and the gas phase, respectively. Reference numeral 25 is a pressure regulating device which, when the gas pressure in the gas phase becomes higher than a certain value (for example, normal pressure),
A part of the gas in the gas phase is configured to be exhausted via the pressure regulator 25. Typically, a check valve or, as shown, an elongated communicating tube inserted into the top wall of the fermentation tank is used. Further, a jacket through which cold water flows is enclosed along the outer peripheral wall of the pressure regulating device main body,
The device may be cooled. In this way, useful components such as ethyl alcohol vapor and acetic acid vapor contained in the gas phase are condensed and reduced to the raw material moromi, improving the yield of vinegar. The shape of the carrier membrane used here is arbitrary, such as flat, cylindrical, etc., as long as it is generally suitable for carrying out the present invention. Further, the membrane may be used alone or may be laminated onto a porous support or a frame-shaped support 26. Further, the number of carrier films may be one, but a large number may be arranged and used at appropriate intervals. In that case, the spacing between the carrier membranes will vary depending on the shape, size, installation method, presence or absence of a blower, capacity, etc. of the carrier membrane, but it is preferable to ensure sufficient gas phase circulation. . The carrier membrane is then arranged tilted to one side, preferably vertically. By arranging it in this way, the vinegar moromi supplied to the upper part of the carrier membrane and permeated therein naturally flows down from the top to the bottom inside the carrier membrane, comes into contact with the acetic acid bacteria that have grown on the carrier membrane, and produces acetic acid. Fermentation can be carried out. It is desirable that the rate of supply of the vinegar mortar to the upper part of the carrier membrane is within a range that does not exceed the permeation rate of the vinegar mortar into the carrier membrane. In other words, if vinegar mortar is supplied in excess of the amount permeated into the carrier membrane per unit time, the excess vinegar will overflow from a part of the carrier membrane, and the acetic acid bacteria film layer that has grown on the carrier membrane. Since the acetic acid fermentation is destroyed and washed away, there is a risk that acetic acid fermentation will not be able to continue vigorously in that area. Next, it is important that the surface of the carrier film is made of a material on which acetic acid bacteria can easily adhere to it. Examples of such materials include cloth and water-insoluble paper that are porous and have a thickness of several millimeters to several centimeters, but lipophilic (hydrophobic) nonwoven fabric and thick cloth are particularly preferred. Specific examples of thick nonwoven fabrics include WOSEP (manufactured by Toyo Rayon Co., Ltd.), Toughnel Oil Protester (manufactured by Mitsui Petrochemical Co., Ltd.), and Teijin Orsorb (manufactured by Mitsui Petrochemical Co., Ltd.).
- OLSORB (manufactured by Teijin), and specific examples of thick cloth include cotton flannel. Next, as a method for attaching acetic acid bacteria to the carrier film, 10 to 20% of the carrier film is placed in vinegar mortar inoculated with acetic acid bacteria.
A method of soaking for a few seconds and then lifting it into the air for several minutes is repeated for several days at a suitable temperature for the growth of acetic acid bacteria, and a method of infiltrating vinegar moromi inoculated with acetic acid bacteria from the upper end of the carrier membrane to infiltrate the inside of the carrier membrane. Examples include a method in which the solution is allowed to flow naturally from top to bottom and leached and dripped from the lower end of the carrier membrane for 20 to 30 hours at a temperature suitable for the growth of acetic acid bacteria.
In this way, acetic acid bacteria can be sufficiently attached to the carrier membrane. The acetic acid bacteria that have grown on this carrier film can be used repeatedly. In the case of batch fermentation, the lag phase is hardly observed from the second fermentation, and when vinegar mash is supplied, acetylation (the action of oxidizing alcohol to acetic acid, hereinafter the same) occurs in a short time. ) begins. Furthermore, even if the supply of vinegar moromi is temporarily stopped due to a malfunction of the equipment, the acetic acid bacteria will not die, and if vinegar mortar is supplied again, vigorous fermentation will start again. The acetylation rate of the carrier film on which acetic acid bacteria have adhered is not much different from the acetylation rate of the bacterial film in the conventional static fermentation method when converted per unit area, and a large number of carrier films are arranged at appropriate intervals in the fermentation tank. By doing so, the bacterial membrane area can be significantly increased compared to conventional static fermentation methods, and the fermentation period can be significantly shortened. Next, examples of the vinegar moromi used in the present invention include vinegar moromi prepared according to a normal vinegar manufacturing method, such as alcoholic beverages such as Japanese sake and grape wine, potatoes, etc.
Examples include alcohol-containing brews obtained by saccharification and alcohol fermentation of grains as raw materials, and alcohol-containing aqueous solutions to which acetic acid bacteria nutrients (for example, sake lees infusion) are added. Since fermentation is carried out in a closed system, it is possible to prevent the evaporation loss of alcohol, acids such as acetic acid, and water, which are components of vinegar moromi, as much as possible during acetic acid fermentation, thereby improving the yield of acetic acid from alcohol, that is, the yield of vinegar. rate increases significantly. However, since it is carried out in a closed system, the oxygen concentration in the gas phase of the fermentation tank is measured, and when the oxygen concentration drops, oxygen is supplied to maintain the oxygen concentration at 5 to 60%. This is extremely important; if the oxygen concentration is too high or too low, the acetylation rate will be slow and the flavor will deteriorate. Examples of the oxygen used here include air, a highly concentrated oxygen-containing gas with an oxygen concentration of 20% (V/V) or more, and pure oxygen. When using air or a high-concentration oxygen-containing gas as oxygen, gases other than oxygen (e.g. nitrogen gas) remain in the gas phase without being utilized as the fermentation occurs, so the oxygen concentration in the gas phase is When trying to maintain a single point concentration close to that of the supplied oxygen-containing gas,
This nitrogen gas must be discharged out of the fermentation tank from the pressure regulator, but in most cases it is not possible to separate oxygen gas and nitrogen gas from the gas phase and discharge only the nitrogen gas from the pressure regulator to the outside of the tank. Since this is impossible, in order to maintain the oxygen concentration in the gas phase at a constant concentration for a long period of time, the amount of air supplied will increase, and a huge amount of exhaust gas will be emitted from the pressure regulator, resulting in the loss of useful components of the moromi. There is a risk of dispersion. Therefore, in this case, the oxygen concentration should be set at two points, the upper limit and the lower limit, within the above range, and when the oxygen concentration reaches the lower limit, air is supplied to increase it to the upper limit in a short time. Since the amount of air supplied only needs to be small and the exhaust gas also becomes small accordingly, useful components such as alcohol are prevented from escaping. In other words, when air is used as oxygen, the oxygen concentration in the gas phase is set at an arbitrary upper and lower limit within the range of 5 to 19%, and when the oxygen concentration reaches the lower limit, air is supplied to remove the oxygen. The concentration is increased to the upper limit value in a short period of time, air supply is stopped, and this operation is repeated intermittently thereafter. In particular, when the upper limit is in the range of 13 to 17% and the lower limit is less than that, the amount of air supplied may be even smaller, and therefore, the escape of alcohol, etc. is almost eliminated. However, if the upper limit is set to 18% or 19% and the lower limit is less than 18% or 19%, if the gap between the upper and lower limits is less than 2%, it will be necessary to constantly supply air. increases, and the yield of vinegar decreases. Therefore, it is preferable to set the lower limit value with an interval such that the upper limit value and the lower limit value are 2% or more, preferably 3% or more. Next, when using a high-concentration oxygen-containing gas of 21% or more as oxygen, set arbitrary upper and lower limits for the oxygen concentration in the gas phase in the fermentation tank within the range of 5 to 60%. When the concentration reaches the lower limit, a high concentration oxygen-containing gas is supplied to increase the oxygen concentration in a short time. At this time, the higher the purity of the oxygen concentration, the smaller the amount of air supplied and the smaller amount of exhaust gas, which can prevent useful components from escaping with the exhaust gas. Furthermore, when pure oxygen is used as oxygen, all of it is used for acetic acid fermentation, so almost no exhaust gas is discharged to the outside of the fermentation tank via the pressure regulator 25.
Since the escape of alcohol etc. can be prevented, the yield of vinegar is significantly improved. Next, the moromi after the acetic acid fermentation is leached and dripped from the lower end of the carrier membrane, and accumulates at the bottom of the fermentation tank. This is taken out from the moromi discharge pipe 24, and the vinegar moromi corresponding to the taken out moromi is transferred to the fermentation tank. Reservoir 3
Vinegar can also be produced continuously by replenishing water. In addition, if the fermentation is not completed after the vinegar moromi flows down the carrier membrane once, either the moromi accumulated at the bottom of the fermentation tank should be circulated to the fermentation tank again, or the carrier membrane should be tilted instead of vertical. The contact time, contact amount, and contact area between acetic acid bacteria and vinegar mash can be adjusted by making the carrier film longer, by making the shape of the carrier film wider toward the bottom, or by making the structure of the carrier film denser. Acetic acid fermentation can be completed by increasing . Next, the fermented moromi obtained in this way is taken out from the fermentation tank, and then subjected to aging, filtration, and standardization of ingredients, followed by sterilization to produce a product according to the usual vinegar manufacturing method. As is clear from the above explanation, the present invention involves arranging a large number of porous carrier membranes with large surface areas and on which acetic acid bacteria are attached at appropriate intervals in a closed fermentation tank, and fermenting vinegar moromi. Since it is supplied to the upper part of the carrier membrane and allowed to flow down the carrier membrane by gravity to contact the acetic acid bacteria and fermentation is carried out, compared to the conventional static fermentation method, the bacterial membrane area can be significantly increased, and the fermentation The period can be drastically shortened. Furthermore, unlike the conventional submerged aeration agitation method and dripping fermentation method, the vinegar moromi is not brought into violent contact with bubbles or air, but instead the acetic acid bacteria and the vinegar moromi are brought into gentle contact within the carrier membrane. Since the method prevents the moromi from coming into direct contact with air as much as possible, and only acetylates the acetic acid bacteria as rapidly as the submerged aeration stirring method, the excellent aroma of the raw sake, which is a component of the vinegar moromi, is lost. This is a high-quality vinegar that is excellent in terms of aroma, taste, and overall taste, without causing unnecessary oxidation due to the vinegar moromi coming into contact with air, and producing unpleasant aromas and tastes. It can be obtained using simple equipment and in a very short period of time. Additionally, since the fermentation is carried out in a closed system, the evaporation and dissipation of alcohol, acid, water, etc., which are useful components in the vinegar mash, can be prevented as much as possible during the acetic acid fermentation, and vinegar can be obtained in a high yield. can. The present invention will be explained in more detail below with reference to Examples. Example 1 The fermentation tank 1 is a closed box-shaped tank measuring 40 cm in length, 26 cm in width, and 28 cm in depth. Rayon Co., Ltd.' were coated with 17 pairs (the total effective area of the carrier film was approximately 1.5
m ² ) are set up at 10 mm intervals with their upper ends aligned almost vertically, and a "means for supplying and permeating the vinegar mortar to the upper part of the carrier film" is inserted into the through groove 4 provided on the bottom wall of the mortar retention tank 3. The upper end of the carrier film is inserted to create a structure that does not leak water, the oxygen concentration detection element 9 is an RA oxygen meter for both air and liquid use manufactured by Oriental Electric Co., Ltd., and the oxygen concentration control device 10 is manufactured by Yamatake Honeywell.・Controller, 0-100% system", the temperature control devices 16 and 20 are Dimroth type cooling pipes, and "means for returning the moromi leached and dripped from the lower part of the carrier membrane to the fermentation tank as vinegar moromi" is installed in moromi tank 1.
1 and the mash supply pipe 5 are connected through a pipe 12 equipped with a circulation pump 13, and a pressure regulating device 25 is used.
was set as a long and thin communicating tube with an inner diameter of 1 mm as shown in Figure 1. Incidentally, the amount of circulation of the moromi by the circulation pump 13 was made equal to the natural fall amount of the moromi that leached out and dripped from the lower end of the carrier membrane. In the mortar tank 3 shown in Figure 1, vinegar moromi 20 [acidity 1% (W/V), alcohol 5% (V/V)] prepared using rice vinegar, sake and water and mixed with acetic acid bacteria is added. the oxygen concentration detection element 9 and the oxygen concentration control device 1
0 automatically opens and closes the control valve 7 of the air supply pipe 6, and when the oxygen concentration in the gas phase reaches the lower limit of 7%, air supply starts and reaches the upper limit of 12%. At that time, the supply was stopped, the oxygen concentration was maintained in the range of 7 to 12%, the temperature in the fermentation tank was initially maintained at approximately 30°C, and batchwise acetic acid fermentation was started while circulating the moromi. When the temperature of the gas phase of the fermentation tank exceeds 30°C, cold water is passed through the temperature control device 16 to lower the temperature of the mash, and the mash is returned to the fermentation tank 3 via the circulation pump 13 to lower the temperature inside the fermentation tank to 29°C. Control at ~31°C. Further, the gas phase was continuously blown out and returned to the fermentation tank via the gas circulation device 19, and the gas phase was caused to circulate between the carrier membranes to make the oxygen concentration uniform, and fermentation was carried out. Next, the whole amount of the moromi after acetic acid fermentation is pumped out from the fermentation tank, and the carrier film with the acetic acid bacteria attached is left as is, and the same amount of new vinegar moromi with the same composition as above is charged again, and the acetic acid fermentation is carried out twice. ,
When the change in acidity over time was investigated for each, the results shown in FIG. 2 were obtained. From this result, in the case of the first time, a lag period of about 2 days is observed, but in the case of takeover (second and third time), this is not observed, and acetylation starts immediately, and the acetylation rate increases. It can be seen that vinegar with an acidity of about 7% can be obtained in about 40 hours, which is slightly faster than the first time. Example 2 In acetic acid fermentation carried over from Example 1,
The process was carried out in exactly the same manner as the acetic acid fermentation carried out in Example 1, except that the thick cloth "Toughnel Oil Plotter (manufactured by Mitsui Petrochemicals)" was used instead of the non-woven cloth "Wosep (manufactured by Toyo Rayon)". For comparison, in the fermentation tank shown in Figure 1,
The carrier membrane on which acetic acid bacteria have grown, the retention tank, and the lid that seals the fermentation tank are removed from the fermentation tank to create an open fermentation tank.The same raw material mash as above is charged into this tank, and the temperature inside the fermentation tank is adjusted. Vinegar was produced by a conventional static fermentation method while maintaining the temperature at approximately 30°C. In the above two methods, the acidity of the obtained moromi,
The period required to complete the fermentation and the yield of acetic acid from alcohol were investigated, and the results shown in Table 1 were obtained.

[Table] From the results in Table 1, the static fermentation method of the comparative example requires a long period of 28 days to complete the fermentation, and there is a large amount of evaporation and loss of alcohol etc. during the acetic acid fermentation. It can be seen that the acidity at the end of the process was low, and the yield of acetic acid from alcohol was very low at 60% of the theoretical value. On the other hand, in the classification of the present invention, the period required to complete fermentation is 40 hours, which is extremely short (about 1/17) compared to 28 days in the comparative example, and the yield of acetic acid is low.
It can be seen that the rate is extremely high at 92%. Next, the vinegar obtained according to the present invention category in Table 1,
Training on sensory testing of comparative example vinegar (all vinegars prepared to an acidity of 5%) obtained by the static fermentation method, which is said to produce vinegar with the best aroma and taste among various vinegar manufacturing methods. When the test was carried out by a panel of 20 people, the results shown in Table 2 were obtained.

[Table] From the results in Table 2, the vinegar obtained by the present invention was evaluated slightly better than the vinegar obtained by the static fermentation method. It turns out that vinegar can be obtained. Example 3 In the vinegar production method carried over from Example 1, pure oxygen gas was used instead of air, and when the oxygen concentration in the gas phase decreased to 17.5%, pure oxygen gas was supplied into the gas phase to reduce the concentration to 22.5%. The acidity
7.4% vinegar could be obtained 30 hours after preparation.
The yield of vinegar was 98.0%. Example 4 In the vinegar brewing apparatus used in Example 1, one side of the carrier support frame 26 made of vinyl chloride was covered with a thick cloth "Toughnel Oil Protzer (manufactured by Mitsui Petrochemicals)". Vinegar mash 22.6 [acidity ^2.0 % (W/ V), alcohol 4.9%
(V/V)], and the acetylation treatment was carried out in exactly the same manner as in Example 1, except that pure oxygen gas was supplied to maintain the oxygen concentration in the gas phase in the fermentation tank at 15 to 20%. As a result, 47 hours and 30 minutes after preparation, the acidity was 8.1%.
of vinegar was obtained. Example 5 The entire amount of fermented moromi was taken out from the equipment used in Example 4, and a new vinegar moromi 22.2 (acidity 1.2%, alcohol 4.5%) prepared using seed vinegar, sake and water was added and carried out. Acetylation treatment was carried out under the same conditions as in Example 4, and 30 hours after brewing, 4.9 g of sake (15% alcohol) was poured into the moromi at a rate of 180 ml/hour. As a result, vinegar with an acidity of 9.2% 63 hours after preparation.
27 was obtained. Example 6 In acetic acid fermentation carried over from Example 1,
Using 21 pairs of vinyl chloride carrier support frames 26 covered with thick cotton flannel on both sides (the total effective area of the carrier film is approximately 1.9 m ² ), the stagnation tank 3 shown in Fig. 1 was constructed. Vinegar moromi prepared using seed vinegar, sake and water
18.8 (acidity 1.6%, alcohol 3.2%),
Example except that pure oxygen gas was supplied to maintain the oxygen concentration in the gas phase in the fermentation tank at 15 to 20%, and sake 5 (alcohol 11.9%) was injected into the moromi at 174 ml/hour from 59.5 hours after brewing. Acetylation treatment was carried out in exactly the same manner as in 1. As a result, 97 hours after preparation, vinegar with an acidity of 7.5% was found.
23.8 was obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal schematic explanatory diagram showing one specific example of the vinegar brewing apparatus of the present invention, FIG. 2 is a diagram showing changes in acidity over time of the vinegar brewing method of the present invention, and FIG. 3 is a diagram showing changes in acidity over time. FIG. 3 is a diagram showing changes in acidity of vinegar moromi over time. In Fig. 3, ○-○ indicate Example 4.
, △-△ is a curve of Example 5, and □-□ is a curve showing a change in acidity over time of each vinegar mortar of Example 6. 1... Fermentation tank, 2... Carrier membrane, 3... Retention tank, 6... Air supply pipe, 8... Oxygen supply source, 9...
oxygen concentration detection element, 10... oxygen concentration control device,
25...Pressure regulating device.

Claims (1)

[Scope of Claims] 1. In a closed fermentation tank, a porous carrier film on which acetic acid bacteria are attached is arranged vertically or inclinedly, and vinegar moromi is supplied to the upper part of the carrier film and permeates into the carrier film. A method for brewing vinegar, which is characterized by flowing down the inside of a carrier membrane, contacting the acetic acid bacteria, and carrying out acetic acid fermentation while maintaining the oxygen concentration of the gas phase in the fermentation tank at 5 to 60% (V/V). . 2. Adjust the oxygen concentration in the gas phase in the fermentation tank to 5-19%.
(V/V) A patent claim that repeatedly maintains an operation of supplying air to quickly raise the oxygen concentration to the upper limit when the oxygen concentration reaches the lower limit with arbitrary upper and lower limits determined within the range of The method for brewing vinegar according to item 1. 3. Reduce the oxygen concentration in the gas phase in the fermentation tank to 5-60%.
(V/V) When the oxygen concentration reaches the lower limit value, the oxygen concentration 21
% (V/V) or more of a high concentration oxygen-containing gas to rapidly raise the oxygen concentration to an upper limit value. 4. The vinegar brewing method according to claim 1, in which acetic acid fermentation is carried out while supplying pure oxygen to maintain the oxygen concentration in the gas phase in the fermentation tank at 5 to 60% (V/V). . 5. A closed fermentation tank, a porous carrier membrane on which acetic acid bacteria are attached, which is arranged vertically or inclined in the fermentation tank, and means for supplying and permeating vinegar moromi to the upper part of the carrier membrane. A vinegar brewing apparatus comprising: a means for controlling the oxygen concentration in the gas phase of the fermentation tank; and a means for returning and circulating the leached moromi from the lower part of the carrier membrane.