Instructions for assemblage and use of the SJA Fermentograph Type JM 451
Packing of the Fermentograph
On delivery of the SJA Fermentograph all parts ar packed separately. In order ro protect some delicate parts of the apparatus these have been removetd from their regular positions and are packed separeately in the case, whilst other parts are espcially protected in their positions on the apparatus.
This refers to the contact thermometer and the floats, inter alia.
Assemblage the Fermentograph
Unpacking is done carefully and the apparatus is taken out and put on its proper place. The foundation should be stabel and have smooth surface.
The Fermentograph is trued up with care.
The three covers on the top of the recorder are removed, the floats are taken out, the corrugated cardboard wrapped round the floats is removed, after which the oil is filled into the apparatus as described below.
Filling of oil
Each float chamber is filled up with approx. 2470 ml paraffin oil, at which the distance from the oil level to the upper edge of the chamber should be 320mm.
Note: The floats should be taken out when the oil is added.
The floats are now introduced carefully and the covers of the chambers are replaced in their right positions. Through the little threaded hole with plug on the cover of the float chamber the oil level is now checked to be the same in all three chambers. This is checked with the supplied little gauge rod, in which a mark indicated the right oil level. This should then be checked in regular intervals.
The covers over the floats on which the diagram clockwork are mounted are now screwed on and it is checked that the diagram clockworks are in absolutely vertical positions. These are then connected by the contact plugs to the electric system of the apparatus. Some parts are very delicate, such as the writing pen etc.
The contact thermometer is now carefully taken out and mounted on its place on the top of the Fermentograph.(The connection on the back is for the contact thermometer and the front connection for filling of water.)
The contact thermometer is connected to the electric network of the apparatus with the contact plug. By turning the upper cap of the thermometer the contact thermometer should be adjusted so that the temperature in the apparatys becomes exactly 35,0o C.
Water is filled into the apparatus, the water level being governed by the little overflow pipe under the electric switch box, where excessive water is running out. Preferably, distilled water (approx 70 litres) should be used. If city water is employed, this will still be stinking after some time in the apparatus.
Note: We recommend some anti-rust fluid to be added to the water. (Same type as available for car engines cooling water.)
The Fermentograph is now connected to the electric network.
The apparatus is made out for 220 V one-phase alternating current 50 cycles.
A control thermometer is introduced in the water-filling hole. With this themometer the contact thermometer is checked to give the right temperature of 35,0o C. Should the temperature of the contact thermometer not agree with the control thermometer, the contacts may have been damaged in transit. If, for instance, the mercury in the contact has split, this may be corrected by light heating of the thermometer in a water bath, or by gentle knocks in its longitudinal direction.
Directions for use of the Fermentograph
- The diagram paper is put on the drums, which can be done without disengaging the drum. The paper sheet is fastened to the drum with the spring and should fit tightly to the wall and lower edge of the drum.
Adjust the pen so that in its lowered position is put on the zero point of the paper when the float is emerged entirely. Correction is done with the adjusting screws on the penholder. The pen is put up again.
- When not being employed, the moulds should be kept in the fermentation chambers to always have the same temperature as the apparatus. If cooled tools are used or the door of the fermentation chambers has been open for a long time before the sample is introduced, incorret values will be obtained.
- A dough is prepared as per the recipe attached and out in the mould being pre-heated in the apparatus and the mould is replaced into the fermentation chamber.
- The door of the fermentation chamber is put in carefully with due observance of the little airscrew on the cover being open. The door must not be put in violently. The pen is put down to the diagram paper and the switch for the diagram clockwork is closed. After approx. 15-30 seconds the air valve is shut. The timer on the front of the fermentation chamber in question is set to exactly 60 minutes.
- The fermentation is allowed to continue until a signal is obtained on the timer, at which curve no. 1 on the enclosed diagram sheet is obtained. The pen is put up, the air valve in the door and the door itself are opened, the mould is taken out, after which the dough is kneaded rapidly by hand (meanwhile the door should remain loosely in its place so that the door and the chamber do not get cooled.) The dough is put into he mould again, which is introduced to the fermentation chamber once moore. The door is replaced and shut. Then the diagram drum is turned back and put on zero again, as described above. The pen is put down at zero. At last the air valve in the door is shut. The timer is set at 60 minutes and curve no. 2 is obtained.
- After another kneading and introducing of the mould, as described above, curve no. 3 is obtained.
- At subsequent baking tests of the yeast which has been kept in a thermostat or in a package it is convenient to start on “1 h” of the diagram paper, so that the curves for these tests will be on the second hour of the sheet, at which curves no. 4 are obtained
Testing the fermentation energy of yeast in SJA Fermentograph
SJA Method IV, 1a
1a. Dough fermentation test with salt solution and fresh yeast
The fermentation force of yeast signifies by the time reqiured by a certain yeast quantity to develop 450 ml carbone dioxide under determined conditions in the SJA Fermentograph.
Wheigh 280 g wheat flour (standard quality), in a suitible tin box with cover and let it get tempered in a thermostat to 35C for some hours overnight.
- 2,5% commom salt solution
Dissolve 25 g natrium chloride, chemically pure, (commom salt) in destilled water to 1000 ml. The salt solution is preferably kept in a storing bottle with siphon in the bakery or the laboratory, where the fermentation test is made.
Preparation of dough:
Heat 160 ml saline solution to 30C and pour it dowin into the mixer. The tub of the dough should be kept at room temperature. Add 5 g yeast and stir it out carefully. Add the tempered flour, start the mixer and let the dough kneading continue for exactly 5 minutes (corresponding to 388-390 revolutions). The dough temperature should be 30C.
Take the kneaded dough out from the mixer and put a thermometer in the dough to measure the dough temperature, which should be 30C. The thermometer should be checked with a standard thermometer. If the dougt temperature would no be 30C – that is above or below 30C – this may depend on the room temperature beint too high or too low. The salt solution should then be made somewhat colder or warmer than 30C before adding, which must be decided in each case.
Form the kneaded dough by hand to a loaf and put it, wiothout specially packing, into the mould and then into the Fermentograph, which should be 35C. Screw the door of the fermentation chamber on, at which the small air valve on the door should be open.
Fix the writing pen at zero on the diagram paper and shut the valve. Let the dough ferment for 60 minutes. After this procedure, open the valve, screw the fermentation door off and teke the mould out. Knead the carbone dioxide out, by working the dough by hand, replace the dough into the mould and put it back into the fermentation chamber. Screw the door on, shut the valve, turn the diagram drum back to the startpoint at zero and let the dough ferment for another 60 minutes.
After this second fermentation, repeat the procedure once more. After the third fermentation, take the mould out and place it in a thermostat cablnet for a finishing fermentation for 30 minutes at 35C. Then bake the bread at 250C for about 15 minutes.
The fermentation time of the tested yeast could be found in the table overleaf, by following the carbone dioxide volume that is read off from the diagram sheet after the first hour. Then the fermentation time must be corrected for air pressure and if required, to 25% dry yeast substance.
Correction of fermentation time to 760 mm air pressure:
Reached time for 450 ml carbone dioxide = 45 min at 740 mm air pressure. Calculated to 760 mm air pressure:
740*(450/760) = 438
Correction of fermentation time to 25% dry yeast substance:
Yeast with a dry substance percentage of 27% has given a fermentation time of 46 min at 760 mm air pressure. The fermentation time of 25% dry substance percentage is calculated to:
Correction of carbone dioxide volume to 760 mm air pressure:
Reached carbone dioxide after 2 hours at 740 mm air pressure = 1400 ml. Calculated to 760 mm air pressure:
Correction of carbone dioxide volume to 25% dry yeast substance:
Yeast with a dry substance percentage of 27% has given 1363 ml carbone dioxide. The volume carbone dioxide at 25% is calculated to:
Fermentation test according to SJA Method IV, 1a, 1b and dry yeast
Fermentation time in minutes, corresponding to the volume of the carbone dioxide developed after the first fermentation hour.
Fermentation time = number of minutes required to develop 450 ml CO2.
|After 60 min, CO2 ml||Ferment. time, minutes||After 60 min, CO2 ml||Ferment. time, minutes||After 60 min, CO2 ml||Ferment. time, minutes|
Instructions for the calibration of the Fermentograph
Connect the hose coupling in the bottom of the Fermentograph.
Unscrew the door vent valve screw. Pull out the piston pump to the upper position and connect the hose coupling in the door vent valve. Make sure that the pen is in zero position.
Place the Fermentograph in vertical position and press the piston pump slowly to the bottom position. The pen shall now display 1000ccm. Let the equipment be connected for one hour. The pen shall indicate the same value after one hour. If it does, the Fermentograph is OK.
The air pressure must be constant during the test.
Control the other chambergs in the same way.
In case of problems with the float
Blow air in the door vent valves so that the float are rising to cc 900 by way of example in all the three chambers. Shut the valves.
After 60 minutes they shall be equal and att the same level as they where before starting the test.
If the float have been sinking there can be a leak. Change the door of the fermentation chamber and repeat point 1.
If the same float have been sinking again, then change the float by loosing the cover on top of the float chamber. Opend the cover, lift the float carefuly and change to anonther float chamber and repeat point 1.
If the float are sinking again, the problems is in the float. Then you have to inspect the float through weighting it in the oil-chamber with the pen holder at the top of the float. The weight shall be 20 - 22 gr. If the weight is higher there i probalbyly dough residues in the float. You can remove it or cut of a small piece of the weight-plate under the float. If there is not any dough residues, then shake the float. If there is a splashing sound there is oil in the lower part and you must order a new float from us.