Operation and Processing Manual
Pressure-puffing machine(Yoshimura-Model)This manual explains the operation and maintenance of your pressure-puffing machine(Yoshimura-Model). Please read it thoroughly and follow the instructions carefully.
Doing so will help you enjoy many years of safe and trouble-free operation. Sample ofprocessing puffed cereals also described at the end.

Acknowledgement
Financial Contribution: Japanese Ministry of Agriculture, Forestry and Fishery (MAFF).
This publication was prepared in partnership with the following institutions and individuals. Their valuable
contribution is highly appreciated.

Author: Yasu Morimoto (Bioversity International)
Resource persons: Kaoruko Ieda (Ieda confectionary co Ltd, Japan), Fumiaki Yoshimura (Pongashiki sale,Japan), Francis Oundo, Lucy Munyoki, and Daniel Kirori (DK engineering co Ltd, Nairobi), Peninnah
Mwangangi and Syokinili Women Group Kitui County, Gichangi Mahinda (Gichangi Cereals and Spices
Embu County), John Kimutai and his family in Bomet County, Charls Mogeni and Okonyo Migori Self
Help Group, Migori County.
Editors: Yasu Morimoto, Patrick Maundu (National Museums of Kenya), Shinichiro Nishino (Japan Association for International Collaboration of Agriculture and Forestry: JAICAF), and Yasunori Kanda (CDCInternational)
Photos: Yasu Morimoto, Dominic Tumbo, Francis Oundo, Isaac Mwangi, Makiko Naganuma, Yumi Yamane, and Kodai Mori.
Design: Shinichiro Nishino (JAICAF), Seiko Fukuda (Nihon University).

Cover photo:Pressure-puff cereal machine in Kitui County, Kenya©Copy right: JAICAF and Bioversity International (2017). All rights received.

1

Contents
Page
Section 1:

Overview of instruments

3

Section 2:

Operation

5

2.1:

Requirements and accessories for operating the machine

5

2.2:

Operating procedure

6

2.3:

Samples of puffed cereals

16

Section 3:

Maintenance

19

Section 4:

Processing and flavoring of puffed cereals

23

4.1:

Utensils

24

4.2:

Flavoring with sugar (standard)

26

4.3:

Potential seasonings

27

4.4:

Chocolate cube

28

4.5:

“kashata” (cereal bar / biscuit)

30

Photo: Local children in Bomet County enjoying the kashata.
2Section 1: Overview of instruments

The machine consisted of three major sections, A: Cylinder, B: Fire place, C: Cereal trap (wire mesh cage)

3

Name1Iron sheet

2

Lid guide3

Hitting peg

4

Cylinder holder

5Funnel6

Pressure gauge

7

Cylinder lid

8Center bolt

9

Mesh guide10

Flame stand11

Shock absorber pad

12

Safety valve

13

Rotating handle

14

Lowering handle

15Slider16

Hooks for cotton bag attachment

17

Hitting peg (same as 3)

18

Peg holding pin

19

Lid guide (Same as 2)

20

Center bold rock bolt

21

Hole for iron rod to tighten the cylinder lead

22

Center bolt (same as 8)

23

Cylinder lid (same as 7)

24

Teflon pressure gasket
4Section 2: Operation
The pressure popping machine or cereal popper is used to produce the healthiest foods and snacks throughaccumulated high pressure by heating the cylinder. It can puff or pop many different kind of cereals andgrains; e.g. Maize, Sorghum, Wheat, Finger millet, Pearl millet, Rice, Beans and Nuts etc. The machine
can use variety of locally available heat sources such as gas, charcoal but this model particularly designed
for using firewood.

2.1. Requirements and accessories for operating the machineName
1 Eye protection
2 Pressure gauge
3 Ear mugs- ear protection
4 Scooping rod- used to clean the machine andremove remaining popped cereals from the cylinder.
5 Rubber hammer- used to open the cylinderwhen the cereal is ready to pop.
6 Skin or woolen gloves
7 Sealing tape
8 Spanners; no; 14, 17, and 19
9 Iron funnel- used to pour the cereals into thecylinder
Iron rod- used to tighten the cylinder lead
Clean cloth
Clean basins and buckets
Lighter for setting fire
Firewood
Serving spoons52.2. Operating procedure
1. Preparation of the materials
Wash, clean, remove stones and dry materials under the sun (a day before the operation). The recommended moisture content of the grains is between 15 and 18 % for best puffing. The moisture contentsof polished rice and wheat grain sold in common markets in Nairobi is between 8 to 13%. Washinggrain therefore important not only for cleaning but also adjusting the moisture contents of the grains.
Recommended to add about 60-80g of water for every 1kg of grains (Rice) if not sure the original
moisture contents. This water adjustment process makes well puffing the grains. However more than
20% of the moisture contents makes grain (Rice) hard and reduces the success ratio of puffing grains.
The grain can be packed, sealed in a plastic bag and stayed overnight after the moisture adjustment.
Sample calculation formula and answer:
Adjusting 10% moisture Rice grain 1kg (1,000g) into 18%.
● Water content of the Rice grain:
1,000g x (10/100) = 100g
● Making 18% moisture content Rice grain:(100+x)/(1,000+x)=18/100
10,000+100x=18,000+18x
100x-18x=18,000-10,000
82x=8,000
x=97.56
Adding water: 97.56g

2. Assemble all the requirements e.g. firewood, clean basins, clean cloth, clean cereal, gloves, etc. Cut thefirewood into small pieces.

6

3.

Confirm pressure gauge clean and put sealing tape on.

4. Check and tighten all the nuts and bolts.

5.

Clean inside the pressure tubes.

7

6.

Put the pressure gauge and make sure it is tight.

7.

Put shock absorbing pad (wooden and/or rubber).

8.

Light the fire in the fire place.

8

9.

When the fire is ready, carefully place the cylinder on the fire place. NB; the cylinder should be open
this time.

10.

Wipe the cylinder using the long spoon and a clean wet cloth

11. Wipe the cylinder gasket using a clean wet cloth912. Rotating the empty cylinder about 7-10 minuets as pre-heating of the cylinder.

13. The cylinder can hold up to 1kg of grains. Weigh 1kg of cereal while the cylinder heats.

14. Lower the cylinder using the lowering bar.

10

15.

Release template inside the cylinder as pour the cereal into the cylinder using the iron funnel

16.

Close and lock the lid by hooking the hitting peg. Then tighten the center bolt using the iron rod byholding the peg tightly with the other hand (use the globes).

17. Start rotating the cylinder using the rotating handle (60-70 rotating per minute, or 10-14 rotating per
10 seconds) as continue adding firewood from the side. Rotating too fast or slow makes material
burnt. Make sure the fire is well maintained while you operate the machine. Ensure you keep rotating
the cylinder.

11

18. Start preparing the cereal trap, attaching cotton bag and keep it near the machine. Keep checking thepressure gauge. Pressure should start increasing after 2-3 minutes and goes slowly upto around 5
M.pa. It increases rapidly after then. NB. Need special attention requires for monitoring the pressuregauge at this time. Keep the clean basin, rubber hummer.

19.

When the pressure reads as per the requirements of the type cereal (See Table 1), stop rotating and set
up the cereal trap in its position (hitting peg supposed to be at the top position).

1220. Once it reaches at the target pressures, set the position of the trap cage. Advice observers to not standin front of the direction of releasing pressure. Hand bell can be useful to alert people nearby. Gently
but surely hitting the peg with the rubber hummer to release pressure. With large explosion sound,
puffed cereal is trapped in the bag.

13

21. Remove the cereal trap quickly and22. Harvest the cereals from cylinder using the scooping spoon and also from the trap and bag.

23.

When the cereals are in the trap, pour then into the clean basin/bucket.

14

24.

Clean inside the cylinder.

25. Put another cereal into the cylinder to continue processing.

26. Sieve and separate defective materials And put selected materials into the bag for next processing.
Defective materials can be grinded into flour for other uses.

15

2.3: Samples of puffed cereals

16Some of the grains the project has puffed (top left to bottom right): Maize (Zea mays); the volume expands
more than 10 times of the original grain size, Maize (Zea mays), Rice (Oryza sativa), Broken Rice (Oryzasativa), Pearl millet (Pennisetum glaucum), Finger millet (Eleusine coracana), Red sorghum (Sorghum bicolor), Bambara nuts (Vigna subterranean), Greengram (Vigna radiata ), and African Marama bean
(Tyloseme fassoglense).
27.

Enjoy eating puffed cereal or add preferred flavors.

17

Table 1. Recommended puffing pressures and methods for major grains.
Materials

Pressures (kg)Method

1 Rice10Puff2 Wheat

9Puff

3 Maize

9Puff

4 Finger millet

11

Puff

5 Sorghum

11Puff

6 Pearl millet

10

Puff

7 Greengram

8-10

Puff or Cool down

8 Lablab

8-10

Puff or Cool down

9 Beans

6

Puff or Cool down

10 Soya beans

6-7

Puff or Cool down

11 Grand nuts

5-6

Puff or Cool down

12 Cowpea

7

Puff or Cool down

13 Bambarra nuts14 Marama bean (EA type)6
6

Puff or Cool down
Puff or Cool down

18Section 3: MaintenanceThe best kind of maintenance is preventative maintenance. Good service and routine checkups can reduced
breakdowns and significantly increase the lifespan of your machine as well as contribute to saving time andmoney.
Inside toolbox

Name
1Toolbox

2

Ear mugs- ear protection Pressure gauge

3

Rubber hammer

4

Sealing tape5

Eye protection

6Skin or woolen gloves

7Tools; spanners, pipe wrench, priers etc

8Scissors

9Knife10Spare parts; pressure gauge, center bolt, hitting peg, Teflon gasket etc.

19

Wipe inside cylinder with clean duster.

Apply cooking oil inside the cylinder to prevent rusting. Remove carbons using iron rod.

Make sure pressure hole is clear.

20

You can clean other parts using water.

Change wooden damper if it is necessary.

21

Make sure all bolts, nuts and pins are tighten and fixed right.

Check thickness and surface of the Teflon gasket. Requires change if it is <than 2mm thickness (standardsize is 5-6 mm). To make gasket surface flat using sandpapers.

22Section 4. Processing and flavoring of puffed cereals.
* Code of practice of the East African standard, Hygiene in the food and drink manufacturing industry will
be applied to all food and drink manufacturing industries irrespective of their size and volume of production.
https://law.resource.org/pub/eac/ibr/eas.39.2001.html

23

4.1: Utensils

Name
1

Plastic buckets, different sizes

2

Wooden “kashata” flames

3

Plastic basins, different sizes

4

Clean cloth

5

Table

6

Stove / Cooker

7

Saucepans

8

Weight balance

9

Kitchen and serving spoons

10

Kitchen knife11

Stainless steel or wooden board

24

Flavoring of puffed cereals depend on the type of consumers being targeted. Some of them preferred flavors include sugar, honey, blue band (bread spread), chili papers, chocolate, cinnamon, and fruit flavors
etc. The puffed cereals are flavored to add tastes and preserve them.

25

4.2: Flavoring with sugar (standard)
Directions
1) Making a sugar syrup
Ingredient

Quantity1

Sugar or/and Molasses

350-500 g

2Salt

2.5 g (one tea spoon)

3

Water

180 mL Step 1: Put sugar and salt into the water and stir and boil continuously for 15-20 minutes over large
heat. Be careful not to let the sugar burn and do not let it crystallize in the bottom of the saucepan.
Never cover the saucepan with a lid.
 Step 2: Never walk away. Continue star to boil over until the mixture begins to thicken and turns
into light brownish in color. It produces a lot of small bubbles where it hardly disappears at thisstage.
 Step 3: Stop heat and pour the mixture (syrup) over puffed cereals all at once and stir with large
wooden spoon for a few minutes to ensure the syrup is well coated and dried.

2) The syrup can be used for most of the products to flavor as follows. Different puffed materials canbe mixed.
IngredientSyrup

1

1 L of puffed sorghum

1 and ½ serving spoon

2

1 L of puffed white corn (maize)

2 serving spoons

3

1 L of puffed wheat

1 serving spoon

4

1 L of puffed rice

1 serving spoon

NB: One serving spoon is approximately 50g of the syrup.

Making sugar syrup (left). Adding syrup to puffed materials (right).
26

Stir with large wooden spoon and ensure the syrup is well coated and dried (left). Serving for testing(right).
4.3: potential seasonings
Various spices can be used as seasonings to create new taste and unique additional values for your original
puffed cereals. It is recommended to use natural products which easily available and accessible.
Potential spices for favoring
Spices and favors

Forms

Quantity (g) for 1L puffedmaterials

1

Coco, Chocolate drink

Powder2.5 (one tea spoon)

2Cinnamon

Powder2.5

3

Roasted soya bean (soya drink)

Powder

2.54Coffee

Powder2.5

5

Green tea

Powder

2.56

BaobabPowder

37

Chili

Powder18

Black paper

Powder

19CurryPowder

210

SaltPowder

211

Soy sauce

LiquidSome

12

HoneyLiquid

2.5

13

Dried mango

Small particles

3 to 5

14

Dried grated coconuts

Small particles

3 to 5

15

Dried pineapples

Small particles

3 to 5

16

Roasted ground nuts

Small particles

3 to 5

17

Roasted cashew nuts

Small particles

3 to 5

18

Roasted sesame seeds

Some

19

Roasted amaranth seeds

Some27

Directions
 Put puffed materials and spices in a same paper bag and shake until the spices are well sprinkled
and mixed with the cereals.
 For salty flavors such as black paper and curry powder, little quantity of olive oil or palm oil ismisted over the cereals and then applied spices.
 Different spices and favors can be mixed and create own unique tastes.

Puffed rice with green tea powder (left) and coco drink powder (right).
Recipe and photos: Makiko Naganuma (2017)
4.4: Chocolate cube
Directions··Engrave cooking chocolate (250g) and melt with a water bath.
Stir slowly until it melts.

28 Put puffed material and adjust the quantities (about 1L). Less material makes it less cube.
·Mix well that chocolate evenly courted around.

·Put it in a mold. This time, a 3cm square ice tray was used.

 Put it in the refrigerator, cool it. It solidifies in about 20 minutes.
Recipe and photos: Yumi Yamane (2017)29

4.5: “kashata” (cereal bar / biscuit)
A "kashata" is a traditional Swahili confectionaly snack popular in East African coast region.
IngredientQuantity

1Puffed materials (mixed in different cereals)

4 L (450-500 g)

2Sugar

160 g

3Salt

6g

4WaterGlucose syrup

100 mL

Other ingredients such as rasted grund nuts, cashewnuts, makademia nuts, grated coconut, dired fruits etc.
can be mixed to add exstra fravours of preference.

Some5
6100 gDirections
Step 1: Mix sugar, salt and water then boil in a saucepan until all the sugar is dissolved (2-3 minutes).
Step 2: Add melted glucose syrup in the pan.
Step 3: Continue star to boil over until the mixture begins to thicken and turns into light brownish incolor. It produces a lot of small bubbles where it hardly disappears at this stage.
Step 4: While preparing the syrup, prepare the “kashata” board (Stainless steel board) and wooden
flames and pour roasted soya powder (also other seasonings) on it.
Step 5: Stop heat and pour the mixture (syrup) over puffed cereals all at once and stir with large wooden spoon to mix the cereal with the prepared syrup in speedy manner.
Step 6: Spreading the materials in the “kashata” flame and apply pressures to shape it. Pressing fromboth sides of the “kashata”.
Step 7: Cutting the “kashata” into favorable sizes and pieces.
Step 8: Remove the flame and ready for packing them.
Note: other additional ingredients such as nuts and dried fruits can be cut into small particles and added inthe kashata.
“kashta” can be served with strong black coffee or tea with ginger.

30

Weigh ingredient (sugar, salt and water) then boil in a saucepan (Step 1).

Preparing the kashata processing board and shaping wooden flame (Step 4).

Pour prepared hot syrup over the puffed cereals all at once and mix well with large wooden spoon(Step 5).

31

Spreading the materials in the “kashata” flame and apply pressures to shape it (Step 6).

Cutting the kashata into pieces using a wooden guide stick and remove the flame (Step 7).

Different sizes and shape of kashata.

32