Here's some data on my lentil malt experiment
Malting procedure:
-thoroughly rinse lentils with cold water
-soak overnight
-drain
-for next two days: rinse and drain a few times a day, storing in a closed container in a cool (~17 C) location
-when acrospire is about the same length as the lentil, dry and roast
I did four congress mashes:
test A: 50 g green malted lentils, not dried or roasted
test B: 25 g 2-row barley malt
test C: 25 g (wet weight) green malted lentils, 25 g 2-row
test D: 25 g dried and kilned malted lentils, 25 g 2-row. The lentils were dried overnight in an oven at the coolest setting, then kilned at 200 F for 1 hour. The resultant malt was crunchy and had a nice lightly toasted flavor.
Each mash test involved crushing each sample in a mortar and pestle before infusing with 200 mL of RO water. The temperature is held at 45 C for 30 minutes, ramped to 70 C over 25 minutes, and held at 70 C for 60 minutes. Temperatures were controlled with a water bath on a hot plate. The mash is then topped up with water to a total mass of 450 g. Normally, this would be filtered, but I just let the malt settle out and sampled the refractive index of the clear liquid above.
The refractive index (in brix) as the tests progressed is as follows
Code:
A B C D
after 30 min at 45C: 1.3 2.4 3.0 4.3
after ramp to 70C: 1.9 6.2 7.8 10.0
after 30 min at 70C: 2.0 7.2 9.0 11.1
after 60 min at 70C: 2.0 8.0 9.3 11.3
after top up to 450g: n/a 3.3 4.4 4.9
I didn't bother topping up the A test, as the extract was so low. Clearly, there aren't enough enzymes in the pure lentil malt to convert the starch. Test A tested positive for starch throughout (using iodine), whereas the the other tests showed no starch after 30 minutes at 70C.
Test B (just barley) resulted in 14.9 g = 59.5% extract, as is. If this is subtracted from C, the lentils contributed 5.0 g extract or 20% (wet basis). The wet lentils were dried to measure their moisture content at 62.2%, which would result in 53% extract (bone dry basis).
The lentils in D contributed 7.15 g extract, or 28.6% extract (as is).
One item to notice is that the pure barley malt mash resulted in a measured extract that is considerably below the typical book values around 80% extract. This may be due to my inconsistent crush with the mortar and pestle.