What is all the fuss about the coffee ‘out-turn test’?
Dr. Kanathanda Manjula Aiyappa (in picture), an agriculture scientist, explains in simple language all that you wanted to know about the coffee ‘out-turn test’ which has become a sort of headache for the coffee planters who are being taken for a ride by the traders.
Dr Manjula, of the University of Agriculture Sciences, Bengaluru, discusses exclusively with www.coorgnews.in about some of the finer points involving the ‘out turn test’ to determine the quality of beans before they are procured by the traders.
Earlier, the prices of coffee were fixed based on the demand and supply in the international market. But now the quality of seeds has become an add-on factor to determine such prices.
The concept of out-turn analysis started in the international market during late 1990s and early 2000 when there was a glut in the market owing to large scale export from all the coffee growing regions without any leash on the quality. Keeping this in view at the International market the concept of out-turn was introduced, also known as Green Bean Equivalent (GBE) to comprehend the quality of the coffee before purchasing from producers.
On May 21st, 2004, the International Coffee Organization (ICO) made it legitimate practice by passing a resolution known as Resolution 420 which is applicable only to beans. Accordingly, 300g of Arabica beans can possess 85g of defective beans whereas, 300g of Robusta can posses 150g. Initially it was in east African region the concept of out-turn was present and gradually it extended across the world. As per the ratio the out turn for Arabica and Robusta was fixed at 1:6 & 1:5 respectively.
For a lay man, it means there should be one kg of beans from at least 5 or 6 kgs of berry/cherry.
So how can growers ensure good out turn to get maximum prices? It is easier said than done as it involves adoption of different best practices.
Recent international research on coffee plantation states that to get ‘A’ grade coffee beans it is not only necessary to have a good genetic background for the plant but other factors also play a vital role, viz., number of healthy leaves in the plant, leaf area, thickness of primary branches, number of secondary branches and their diameter, bush spread, inter-nodal length, age of the plant and quality of fruit produced. All these can be free of defects if only required amount of nutrition, light, moisture and micro-climate is provided. Here even agronomic practices for the plantation demands skilled labours especially for pruning, side shoot removal etc., or else it may also affect the produce.
Coffee plant needs all the 16 nutrients, especially 6 major (nitrogen, phosphorus, potash, calcium, sulphur, magnesium) and 7 minor (copper, zinc, manganese, iron, boron, molybdenum, chlorine) nutrients.
These nutrients are not only to be provided through chemical fertilizers but also through green manures and organic manures. For good quality of cherries/beans the important nutrients required in right amount are phosphorus, calcium, sulphur and boron. All these nutrients are provided through soil medium so it is necessary to get the soil tested for nutrients periodically and supplement the required quantity through correct form, amount and right time.
On the basis of this GBE even the pricing should done uniformly all over looking to the international market rates. Right now the traders operating in these traditional coffee growing areas of South India fix the GBE or out-turn ratio which is like based on the 50kg standard bag of coffee marketed. The 50kg should yield them a minimum of 26.5kg out-turn i.e., for robusta the ratio would be 2.65:5 (2.65kg of beans for 5kg cherry) while the international standard according to ICO is 1:5 or even upto 1:7.
Also along with this there is need to have a huller of uniform make to get similar out-turn/ output in the trading centers than each one calibrating the ratio according their convenience or availability of inputs.
Henceforth for south India GBE ratio has to be fixed for coffee based on region, variety and sampling procedure which also to be fixed for uniform results which needs thorough research and interventions by the concerned for the up-liftment of the farmer especially small and marginal ones.
Tips to make your GBE better!
1. Immature, greenish, over dried, over ripened cherries give poor out-turn. So grading to be done before drying.
2. The unequal distribution of nutrients to all cherries in a coffee plant, rust affected and berry borer infestation also lead to poor out-turn. So management of nutrition, pests and diseases play a vital role too.
3. The growers must ensure they have the right variety and quality coffee plants/seedling that suit their region. Obtain plant material from registered sources.
4. The picking should start when the green cherry/fruit turns pink or pinkish red. But lot of factors also play role in the timing of maturity. More the number of picking lesser will be the outturn
as the cherry ripens, more it adds to the weight of pulp & skin not to the beans.
5. Method of sampling has been standardized in some international coffee growing areas which needs to be implemented here in South India. Promotion of Sustainable Arabica production practiced in North West region, Cameroon can be incorporated. There a sample of 0.5kg is taken from the every 50kg bag and it is pooled and hulled. A random sample of 300g is taken from the pool and tested for defects and outturn results.
6. Dry weather prevailing while flower to fruit set and harvesting time also lowers the outturn ratio. Improving shade can sometimes avert such effects.
7. Providing water at right quantity during fruit set increases the yield but may reduce the outturn and vice versa also shall happen as all these depend on in built nature of the plants in the coop.
8. The drying of cherry or seed to international standard is necessary. The moisture in the coffee should not be lesser or over dried i.e., moisture should not fall below 8 per cent, or more than 12.5 per cent. The moisture content in the seeds is measured by the standard moisture meters like Kappa and Tecator moisture meter as per ISO 6673.
(Dr Manjula is Assistant Professor in the University of Agricultural Sciences, GKVK, Bengaluru. Please give your feedback at [email protected])