Cassava Processing: Gari, Flour and Other Products

Who it is for. Beginners with no formal certificate, including school leavers, women's groups and persons with disabilities. National Proficiency I is the first level of Ghana's TVET framework.

Why cassava

• Ghana grows about 22 to 24 million tonnes of cassava a year (2019 to 2021 figures).
• Women dominate the gari value chain. Grating and roasting are heavy work with smoke, and mechanical graters injure people.
• A study of 46 gari producers in Kumasi found a profit margin of about 22% of sales, and the main problems were seasonality and the cost of cassava. Small-scale results depend on place and year, and some older studies found profit barely above cost.
• In Western Region, the Ministry of Food and Agriculture trained about 150 gari and dough processors, mostly women from Shama, Wassa East, Ahanta West and Sekondi-Takoradi, in food safety and clean processing.

How to read this manual

• Every unit has learning outcomes, performance criteria, a range and the evidence your assessor needs. You are judged Competent or Not Yet Competent.
• About 70% of the time is practical (the same split CTVET used for its Oil Palm programme).
• Steps are numbered. Do them in order. A line that ends with a source name in brackets comes from the sources list at the back. A step with no source is standard safe practice or the author's teaching advice, not a measured figure.
• Any number marked example is made up to practise sums. Replace it with your own local prices.
• Every unit ends with a Check yourself of three questions. Answers are in the Teacher Copy.

Competency standard

Range. The training yard, grating shed and roasting area. Evidence. Hygiene checklist; tools list; oral questions.

What is the cyanide danger

Cassava roots contain a harmless-looking chemical (linamarin). When the root is cut or grated, an enzyme in the root (linamarase) releases cyanide, a poison. Cyanide dissolves in water, and it escapes as gas when fermented or cooked material is dried or heated.

What this means for you:

• The peel holds more cyanide than the inside, so peel thickly.
• Grating spreads the poison and gives the fermenting germs a large surface.
• Fermenting is the main step that lowers cyanide in gari-type foods. The longer it ferments, the less cyanide is left. In one study of another cassava food (attieke), fermenting removed roughly 30 to 50% of the cyanide, pressing about 20%, and the last steaming about 15%. So every step counts.
• Roasting drives off cyanide gas and destroys the enzyme.
• Short-cuts are dangerous. Gari made by hand in one study still had cyanide above the 10 ppm "safe level" in all samples. A permanent paralysis called konzo has struck people who ate badly processed bitter cassava after soaking it for 1 to 2 days instead of 3 to 4 days. It is mainly reported from Congo and Cameroon and is not widely reported in Ghana, but it is a warning to never rush. Eating little protein makes the risk worse.
• You can also breathe in cyanide gas while grating, so grate in a place with good air flow, not in a closed room.

Your hygiene routine

Contact surfaces (tables, graters, pans, sieves) should be stainless steel. Mild steel rusts and contaminates the food. Do not use pans made from scrap engine parts or old radiators, because Ghana-made scrap-aluminium pots have been found to leach lead and other metals. No study tested gari pans, so this is careful advice.

Waste and the neighbours

• Dry peels can be used as animal feed or mulch. Never feed fresh peels.
• Do not throw the pressed juice on the ground. In Western Region, processors were taught to collect juice in a catchment pit because dumped juice smells and attracts animals.
• The wastewater contains starch that can be collected and sold.

Tools and materials you will meet

Prices change often. Ask three sellers and write the answers in your logbook.

Machine and fire safety rules

1. A machine grater can cut off fingers. Guard the drum. Never push roots by hand; use a wooden pusher.
2. Switch off and unplug (or stop the engine) before you clear a jam or clean.
3. Long hair tied up, no loose cloth or scarf near moving parts, closed shoes.
4. Keep the floor around the grater and the pan dry and clear.
5. At the pan, wear a long apron and use a long paddle. Keep children away from the fire.
6. Smoke is a real health risk. Improved stoves take smoke away and cut fuelwood use by about 30% in one project. No measured smoke figures for gari roasting were found.
7. Know where the first-aid kit is. Cool a burn under clean running water for 10 minutes. Do not put oil or toothpaste on it. Take serious burns and cuts to a clinic.

Check yourself: Unit 1

1. Name two ways to reduce cyanide in cassava foods.
2. Why must you never push roots into a motorised grater with your hand?
3. Why should the juice from pressing go into a pit?

Competency standard

Range. One batch of fresh roots. Evidence. Root sorting record; peeling and washing observation.

Choosing varieties

Ask the extension officer or the CSIR Crops Research Institute which varieties grow well near you. Two released varieties named for starch, gari and flour are:

Akwidaa is coastal forest, so check with the CRI or MoFA office that a variety suits your farm (not verified). A 2023 CRI release added four yellow-fleshed varieties (30 to 35% dry matter), but the variety names were not confirmed.

Why dry matter matters: roots with more dry matter give more gari. IITA says a high dry-matter variety gives about 1 tonne of gari from 3 tonnes of roots, while most varieties need about 4 tonnes of roots for 1 tonne of gari.

Harvest

There is no Western Region harvest calendar in the sources, so ask your extension officer which months give the best roots (not verified). Use these steps.

1. Check the age. The two CRI varieties above are ready at 12 to 15 months.
2. Choose a time when you can process all you harvest the same day or the next day.
3. Cut the stem near the base and loosen the soil with a hoe or fork. Pull the roots out gently.
4. Cut the roots from the stem base with a clean cutlass. Avoid cuts and bruises, because wounding starts the rot.
5. Sort on the spot. Keep healthy roots. Throw away rotten, mouldy or discoloured roots.
6. Carry roots in clean sacks or baskets in the shade. Do not carry them far.

Why cassava spoils in 24 to 48 hours

Cassava has a problem called post-harvest physiological deterioration. Blue-black streaks start inside the root within 24 to 48 hours after harvest. The root becomes unsellable and unpleasant to eat. Wounding triggers it. Some reviews say roots are unfit within two to three days.

No source gives an official "process within X hours" rule, but IITA says flour must be made within a day or two of harvest. So the rule for this course is:

Sorting and quality check

1. Snap or cut the end off one root.
2. The flesh should be white (or the colour of the variety), firm and clean. Blue-black streaks, brown rings or a sour smell mean reject.
3. Put roots in three piles: good (use today), doubtful (check again or use first), bad (reject).
4. Weigh the good roots. This weight is your starting weight for the yield count in Unit 3.

Peeling and washing

1. Wash the roots once to remove soil. Use clean water from a protected source.
2. Peel with a stainless steel knife. Remove the brown skin and the cream layer under it, without cutting away the white flesh. Thick peel removal avoids fibrous, dirty gari.
3. Cut off woody ends and any bad spots.
4. Drop the peeled roots into a basin of clean water straight away.
5. Scrub and wash again in clean water. Change the water when it gets muddy.
6. Put the peels in one pile away from the clean roots. Dry them in the sun for feed or mulch. Dried peels only: in a Ghana trial, sun-drying removed cyanide from peels better than ensiling. A safe amount of peels for goats or sheep was not found, so feed only small amounts of dried peels and ask a vet or extension officer (not verified).

Common mistakes

Check yourself: Unit 2

1. How soon after harvest do roots begin to spoil?
2. What sign inside a root tells you it has begun to spoil?
3. Which layers must you remove when peeling?

Competency standard

Range. At least two batches of 20 kg of peeled roots. Evidence. Batch records; finished gari; yield calculation.

Overview of the process

Step 1 · Grate

1. Check the grater is clean and the guard is in place.
2. Feed washed, peeled roots one at a time with a wooden pusher. Mechanical grating is faster, neater and more hygienic than hand grating, with an even particle size and less hard work.
3. Catch the mash in a clean woven polythene sack. Do not let it fall on the ground.
4. Clean the grater at once after use.

Check: the mash is wet, smooth and white, with no big pieces of root.

Step 2 · Ferment

1. Tie the sack closed. Place it on a rack or a clean raised platform, not on bare floor. In Western Region processors were taught to ferment dough in clean basins and not on bare floor.
2. Let it ferment for at least one day. IITA says "one or more days". The CSIR demonstration unit used 36 hours, and a study compared 24 and 72 hours. A common local range is 1 to 3 days (not verified); follow your trainer's rule for your roots and weather and never shorten it for quick money.
3. A fermentation of over 1 to 2 days makes gari very sour. If you like it less sour, press after 1 to 2 days.

Step 3 · Press

1. Place the sack in the press. You can press during the fermentation or at the end of it.
2. Tighten slowly. Press until water stops dripping but the sack surface is still moist.
3. Too little pressing leaves lumps in the pan. Too much gives floury gari.
4. A study aimed for about 40 to 50% water in the mash after fermenting and pressing. The CSIR unit found about 44% water in the dough before roasting gave the best texture. You cannot measure that at home, so use the feel: the cake holds together when squeezed but leaves no water on your hand.
5. Catch the juice in a pit or a bucket.

Step 4 · Break and sieve

1. Take the pressed cake out. Break it up by hand or with a machine.
2. Pass it through a 1.5 to 2 mm sieve to take out fibre and lumps.
3. Put the fibre and lumps aside (or break and sieve again). Do not roast fibre with the good dough.

Step 5 · Roast

1. Wash and dry the pan. Light the fire and bring the pan to even heat.
2. Wipe a little oil into the pan, only a light film. Use oil from a trusted supplier. The FDA found Sudan dye in 24.44% of red palm oil samples it checked in 2024, and there is no safe level of that dye. No gari-specific warning was found.
3. Put in a load of sieved dough. IITA gives 3 to 6 kg per load for a roasting bay. Smaller pans take 2 to 3 kg.
4. Stir all the time with the paddle, scraping the whole pan. In a study the pan was about 130 to 200 °C and a batch took 10 to 17 minutes, with the dough added in 3 to 4 portions. Very high heat on wet dough made it stick and brown.
5. Keep stirring until the gari is dry, creamy-coloured and granular. Taking it off too soon gives white, damp gari. Too much heat burns it.
6. Leave a small amount in the pan for the next load.
7. Tip the gari onto a clean tray or table.

End-point test. A grain of gari should be crisp, break with a snap, and feel dry. The end point depends on the roaster's experience, so practise.

Step 6 · Cool

Spread the hot gari thinly in a clean, covered place, off the ground and away from dust and flies. Do not pack warm gari, because steam makes it damp.

Step 7 · Grade

Use sieves to sort by grain size. IITA gives these sizes.

The Codex standard for gari also sets classes by sieve. Its table is hard to read, so ask GSA or your trainer for the exact figures.

Step 8 · Pack

Pack in plastic-lined sacks (25, 50 or 65 kg), sealed, then store on pallets in a cool dry place for up to a year. Unit 5 gives more.

Yield: how much gari from your roots

• IITA: about 4 tonnes of roots give 1 tonne of gari (25%), and 3 tonnes for high dry-matter varieties (about 33%).
• A Ghana CSIR demonstration unit measured 28% overall recovery from raw cassava to gari. That is one unit's figure, not a promise.

Weigh your own roots and gari every time. That is your real yield.

Common mistakes and fixes

Check yourself: Unit 3

1. Name the eight steps of making gari in order.
2. What happens if you press the mash too little? Too much?
3. How do you know gari is roasted enough?

Competency standard

Range. One batch of kokonte chips and a demonstration of flour or starch. Evidence. Product samples; records; oral questions.

High quality cassava flour (HQCF)

Flour is made from fresh roots within a day or two of harvest. IITA lists these steps.

1. Select fresh roots.
2. Peel.
3. Wash.
4. Grate (or slice or chip).
5. Press to remove water (not needed if you chip).
6. Disintegrate the cake.
7. Sift.
8. Dry.
9. Mill.
10. Screen.
11. Package.
12. Store.

Slicing or chipping can replace the grating, pressing, disintegrating and sifting steps. The minimum equipment is a grater, a press, a solar or flash dryer, a pin mill and a stitching machine. It can be done with simple cottage equipment, much like gari. For cyanide, most of the change happens during drying in the slicing method and after pressing in the grating method. A study in Ghana found sun drying detoxified better than mechanical drying.

Safe level. A cyanide level of 10 mg per kg (10 ppm) is widely quoted for flour. Some experts say it can only be met with low-cyanide roots. Test kits (picrate paper) exist from the Australian National University, but whether they can be bought in Ghana was not verified.

Markets. Ghana studies found that bread with up to 20% cassava flour was acceptable as sugar bread and up to 10% as tea bread. A flash dryer dries fastest but needs steady power. Dryers made in Ghana and their prices were not found. Ghana's CSIR-Food Research Institute ran workshops on high quality cassava chips in several districts.

Kokonte (dried chips and flour)

Kokonte is dried cassava, pounded or milled to flour and stirred into a hot, dark paste. These steps follow what the research found.

1. Peel and wash the roots.
2. Chip or slice thinly: no thicker than about 7 mm.
3. Spread the chips on a raised drying platform or mat, thinly. Black polythene under the chips makes them dry faster.
4. Dry in the sun for 3 to 6 days. Cover at night and when it rains. Turn the chips often.
5. Check dryness. Chips must snap cleanly and feel hard. Damp chips grow mould.
6. Pound or take the chips to a power mill. Sieve the flour.
7. Cool and pack in clean bags.

Defects. Slow drying makes the flour dark. Mould can bring aflatoxin, a harmful poison from mould that was reported as a defect in traditional kokonte. Oven drying gives a whiter product. Flour yield per kg of fresh root was not found, so weigh your own.

Cassava starch (small-scale)

Starch is the white powder in the root. The small-scale steps, as used in tests in Colombia and Vietnam, are:

1. Wash, peel and wash again.
2. Rasp (grate) the roots.
3. Wash the mash on a sieve to take away fibre.
4. Let the milky water stand so starch settles. Do not leave it more than about 10 to 12 hours, because it ferments and smells.
5. Pour off the water, wash the settled starch, and settle again.
6. Dry in the sun or a dryer, then mill.

Two cottage systems recovered 65% and 76% of the starch depending on how well the roots were rasped. Ghana's Ayensu Starch Company at Bawjiase made starch for export; its present status is not verified.

Other cassava foods (know about them)

• Agbelima: fermented cassava dough from the Volta area. Peel, wash, grate, press, then ferment 24 to 48 hours with a traditional starter called kudeme. Studies found lactic acid bacteria dominate, and cyanide falls a lot. Details of preparing the starter in Volta were not found.
• Attieke (from Côte d'Ivoire, also eaten in Ghana): grated cassava is mixed with a starter and a little palm oil, fermented about 12 to 15 hours, pressed, crumbled into grains, dried briefly and steamed for 20 to 25 minutes. A Ghana or Nzema version was not found.
• Tapioca pearls: moist starch is pushed through a sieve, rolled into balls, steamed lightly and dried below 40 °C at first. Small-scale Ghana practice was not found.
• Cassava bread (tempra): no documented Ghana process was found, so it is not taught here (not verified).
• Flavoured gari mixes: the Alloapkoke cassava centre in Ellembelle made gari mixed with wheat, soya, groundnut or ginger. Centre status now: not verified.
• Peels: dried peels for animal feed, only in small amounts.

Check yourself: Unit 4

1. Name three steps in making flour (HQCF) after peeling.
2. How thick should kokonte chips be, and how long do they take to dry in the sun?
3. Why must you not leave settling starch for more than about 12 hours?

Competency standard

Range. One packed and labelled batch. Evidence. Packed bags; labels; oral questions.

Packing

1. Start only when the gari is cool and dry.
2. Use clean, plastic-lined woven sacks of 25, 50 or 65 kg or sealed retail bags. The Codex standard asks for clean, strong sacks that are well stitched or sealed.
3. Weigh each bag on a checked scale. Fill to the exact weight.
4. Squeeze out the air. Seal the plastic liner with a heat sealer (a hand impulse sealer packs about 100 packs per hour) or fold and tie it.
5. Close the sack by stitching (a bag stitcher does about 1 bag a minute and needs a small generator) or by hand.
6. Label every bag.

Storage

• Store sealed bags on pallets, off the floor, away from walls.
• Keep the store cool, dry, clean and free of pests. Shelf life of gari is up to one year when well dried and stored this way.
• The Codex limit for moisture is a maximum of 12.0%. Gari for hot places and long journeys should be even drier. A Ghana sample study found 8.1% moisture.
• Use first in, first out: sell the oldest first. Check bags for damp, insects and smell every week.
• Kokonte and flour need the same dry, clean storage; mould is the main danger.

Labels

• The Codex standard says the name on the pack must be "gari". For non-retail containers, the pack must show the product name, a lot number and the name and address of the maker or packer.
• Ghana's FDA general labelling page lists the usual items: English, name of the food, net weight, ingredients, date of manufacture, best-before date, batch number, maker's name and address and storage instructions. Check the FDA site for the current rules before you print labels (not verified here).

Sample label (example).

Gari (fine grain)
Ingredients: cassava, palm oil (if used)
Net weight: 1 kg
Batch: 12 Oct 26 A
Date made: 12 October 2026 · Best before: 12 April 2027 (example)
Made by: (your name, address, phone)
Store in a cool, dry place. Keep closed.

The rules: FDA and GSA

FDA (Food and Drugs Authority). The FDA registers food businesses and products. Small producers enter through the Progressive Licensing Scheme, with three stages shown as pink (level 1), yellow (level 2) and green (level 3), after an inspection of how well you follow good manufacturing practice (GMP). The FDA's documents for product registration include your business registration certificate, a certificate of analysis for each product, the product label, the facility fee and samples. A facility licence comes first.

Fees (FDA Fee Schedule, 2023). Locally made food: annual charge micro GH¢100, small GH¢200, medium GH¢300, large GH¢500. Licensing of a manufacturing or storage facility GH¢100. GMP inspection (small-scale food line) GH¢200. Food distribution van licence GH¢60. Another FDA page gives product registration (valid three years) as GH¢150 for cottage, GH¢450 small, GH¢600 medium and GH¢900 large. The two lists do not match perfectly, so always ask the FDA office for the current fee.

The Western Region FDA office trains food vendors for food vending permits.

GSA (Ghana Standards Authority). GSA keeps the Ghana standards. It listed 3,356 standards in 2018, including cassava chips, but a gari or cassava flour standard number was not found. Do not quote a number. Write to GSA to ask: gsadir@gsa.gov.gh or gsanep@gsa.gov.gh. A Ghana Cassava Centre of Excellence plans codes of practice for gari and flour.

Business registration

Registering a business name or company is covered in the Level 3 book of this course. For now, ask your Assembly business office and the Registrar General's Department.

Check yourself: Unit 5

1. What is the maximum moisture of gari in the Codex standard?
2. Why store bags on pallets?
3. Name three things on a gari label.

Competency standard

Range. Batch cost sheet; equipment comparison; one week of records. Evidence. Cost sheets; quotes; record book.

Costs of a batch

One study found a fuelwood use of 52 kg a day in gari processing, and an improved stove saved about 30%. A manufacturer-linked stove claimed up to 56% less firewood (a best case). Fuel cost per bag was not found, so measure yours.

How to price

1. Cost per kg = total batch cost ÷ kg of good gari.
2. Check the market price: ask three sellers of the same grade.
3. Set your price above cost but near the market.
4. If the market price is below your cost, find where the money goes (roots too dear, yield too low, labour too high) before you lower your price.

Margins reported. The Kumasi study found about 22% profit margin. Do not promise yourself that figure: it depends on cassava price, yield and sales.

Cassava prices change with the season. Collect local prices, write the date next to each, and never copy a price from this book. Prices for cassava and gari in Western Region now were not found (not verified).

Equipment: what is available

The IITA gari guide lists these machines and capacities.

Other facts: a Ghana petrol-engine grater gave about 89 kg per hour for places without grid power. A buyer's tender asked for a locally made stainless grater with a 10 HP motor, about 1 tonne per hour. A 2014 project in Ashanti found that no affordable cassava press suited gari makers, and local mechanical presses were large and costly. A CSIR mechanical roaster handled 35 kg per hour but not every sample reached the standard colour.

Prices seen on a classified site (undated, confirm). A cassava grinder (grater) GH¢8,000 in Accra; an industrial cassava squeezer GH¢10,500 in Agona West that takes 10 bags; a dough squeezer GH¢6,000 in Ga East; a 10 HP industrial grinder GH¢18,000 in Agona West. These are only listings. Fabricator price lists from Suame, Kumasi or Takoradi were not found.

How to buy equipment.

1. Get at least three quotes (name, date, price, warranty).
2. Ask to see a machine working with cassava, and ask for a guard on the drum.
3. Check the contact parts are stainless steel.
4. Ask who will supply spare parts and repair it.
5. Compare buying with hiring a grating and pressing service.

Records to keep

Check yourself: Unit 6

1. How do you work out the cost of 1 kg of gari?
2. Why get three quotes for a machine?
3. Name four records a gari business should keep.

Competency standard

Range. The trainee's own plan. Evidence. One-page plan; location check.

Choosing a location

Check with the Assembly whether you need approval or any permit for your site. The EPA permit rules for processors were not verified.

Small business ideas

• Fresh peeled cassava sold to gari makers or chop bars.
• Grating and pressing service: charge per bag of roots.
• Gari in 1 kg bags for shops, schools and chop bars.
• Different grades: extra-fine for some buyers, coarse for others.
• Kokonte flour for homes and chop bars.
• Cassava flour for bakers, mixed with wheat flour in bread.
• Cassava starch for laundry or factories.
• Flavoured gari: with groundnut, soya, ginger.
• Dried peels for feed.
• A selling shop or stall for several women's products.

Markets

Likely buyers are shops, chop bars, school feeding suppliers, bakers (for flour), supermarkets and traders. Exports were only an aim at the Alloapkoke centre and are not verified. Buyers in Takoradi were not found, so visit and ask.

Market yourself

• A clean bag with a good label and a name.
• Free samples at markets, schools, churches and clinics.
• Photos of your clean yard and your gari on WhatsApp.
• Be honest about grades, weights and ingredients.
• Keep your promises on weight and delivery.
• Ask each customer what they want next.

Working in a women's group

Women run many gari businesses. A study of two gari areas found 17 women entrepreneurs, 33 workers and 7 farmers, and also found constraints. A ten-member women's cooperative in Jamam bought cassava from farmers and sold gari. In Ellembelle, the Alloapkoke centre is a group model with processing space for gari, starch and dough. A Nigerian study of a women's cooperative (a foreign example) reported a net income of N14,167.74 a year and a benefit-cost ratio of 1.46.

How a group can work:

1. Share one grater, one press and one yard to cut costs.
2. Buy roots together to get a better price.
3. Use one brand name and one licence, with shared labelling.
4. Write rules: who does what, how money is shared, how decisions are made.
5. Keep one record book and show it at meetings.
6. Training and support: the Ghana Cassava Centre of Excellence plans codes of practice, demonstration farms and a waste plant. Ask your MoFA officer for training; MoFA has trained processors in Western Region.

To register a group or cooperative, see the Level 3 book.

Accessibility: persons with disabilities

Cassava processing has many tasks, so there is work for most people. The table below is our own advice; no Ghana source on this was found.

Always agree with the person what they can do, and do not decide for them.

Check yourself: Unit 7

1. Give two reasons why a cassava yard should be close to the farms.
2. Name two ways a women's group can cut costs.
3. Name two tasks a person with limited mobility could do well in a yard.

1. Why do you peel off the cream layer as well as the brown skin?
2. Name three steps that remove cyanide when making gari.
3. How soon do harvested roots begin to spoil, and what do you see?
4. Why must you stir gari all the time in the pan?
5. What happens if you press mash too little, and too much?
6. If 4 kg of roots give 1 kg of gari, how much gari do 120 kg of roots give?
7. What is the maximum moisture for gari in the Codex standard?
8. How thick should kokonte chips be, and how long to sun-dry?
9. Why should gari be cooled before packing?
10. Name two bodies you must contact for food rules (and what each does).
11. Give the formula for cost per kg of gari.
12. Name two tasks suited to a person using a wheelchair.

Best next reads: the IITA illustrated gari guide (copyright IITA: paraphrased here, not copied); CSIR-Food Research Institute cassava papers; the FDA website; the Hub's Food Processing and Money Skills manuals; Levels 2 and 3 of this course.

What this module does not cover: mechanised lines, quality tests and laboratory work, high quality cassava flour production on a larger scale, FDA product registration in detail, record accounting and growing the business (see Levels 2 and 3).

Every source used in this manual is listed, with links, in the Teacher Copy.