Hydration Index - Chapon Test
1. Remove a portion of grain (ideally 100 seeds) from select points during your steeping process – for example: at steep out and 24hrs into germination.
2. Boil the grains for 60 seconds – can be done quickly by placing the grains in loose leaf tea ball and dipping into boiling water
3. Remove the grains from the water and cut them lengthwise along the crease
Areas of the endosperm which are white and starchy have not been hydrated, areas which are translucent and darker in color have been hydrated. The enzymes responsible for modification are hydrolytic (needing water for both movement and action) and therefore your goal for best modification is to get good/even endosperm hydration.
4. Score each seed as 0, ¼, ½, ¾, or 1 for fully hydrated grains. Each level of hydration is assigned a different point value:
0 = 0 points
¼ = 1 point
½ = 2 points
¾ = 3 points
1 = 4 points
The hydration index value is the sum of scores for all seeds in a sample. The score is calculated for easy record keeping. Results from this test should be recorded over time along with information such as sample variety, protein, seed year, source, malting regime, etc. Over time patterns effecting hydration should arise.
Example Chapon test performed with 25 seeds for 16 different lines:
Parameters which can effect hydration: barley variety, grain protein, water temp, and steeping regime