Lesson 6 - Wort Separation Process Control
This lesson deals with wort separation process control. The different methodologies of measuring and calculating extract recovery are explained and demonstrated. A methodology is explored, as is how to investigate and resolve performance issues with extract efficiency, wort quality, and cycle time.
EBC kg Extract Method
We are told the dry extract of our malt is 80% w/w (80 kg/100 kg), and that the moisture content is 4% w/w (4 kg/100 kg).
Therefore, we first need to work out what the dry weight of our malt is by removing the 4% moisture:
The weight of moisture (water) is worked out as 8,000 kg of malt / 100 x 4 = 320 kg
The weight of malt without moisture is then 8,000 kg - 320 kg = 7,680 kg
We are told that 80% of this dry weight is extract, so we can work out the extract weight added now as 7,680 / 100 x 80 = 6,144 kg
We are told that we have produced 428 hL of wort at SG 1.055 at 13.54 ˚Plato.
The SG needs to be converted to density by correcting for the density of water at 20˚C, which is 0.9982 kg/L.
Wort density = SG x 0.9982 kg/L = 1.055 x 0.9982 kg/L = 1.053 kg/L.
Extract recovered = hL x density x ˚Plato
= 428 x 1.053 x 13.54 = 6,102.3 kg.
Extract efficiency is kg extract recovered as a % of kg extract added.
Extract efficiency is 6,102.3 kg / 6,144 kg x 100 = 99.32%.
IoB l˚ Extract Method
We are told that the malt dry extract is 308.5 l˚/kg and that our moisture is 4% w/w.
The ‘as is’ extract is therefore 308.5 x 0.96 = 296.16 L˚/kg.
296.16 l˚/kg = 296.16/100 hL˚/kg = 2.9616 hL˚/kg.
We have used 8,000kg of malt at 2.9616 hL˚/kg
Extract added is 8,000 kg x 2.9616 hL˚/kg = 23,692.8 hL˚.
We have produced 428 hL of wort at SG 1.055 or 55˚ gravity.
Extract recovered is 428 hL x 55˚ = 23,540 hL˚.
Extract efficiency is the recovered hL˚ extract as a percentage of the added hL˚ extract.
Extract efficiency is 23,540 / 23,692.8 x 100 = 99.35%.