Point of reflection – reconvene

Question 1

What factors determine the mash wort strength?

Answer 1

The mash water:grist ratio, the extract in the raw materials, and the mashing conversion efficiency

A typical mashing ratio is 3 L of water to 1 kg of malt, producing a mash wort strength of S.G. 1.092 or 22 ˚Plato.

Question 2

What is the initial wort sent to the downstream wort boiling device called?

Answer 2

Strong worts

Strong worts tend to adhere to the husk residues in the grain bed.

Question 3

How do brewers ensure good extract efficiency from spent grains?

Answer 3

By using hot sparge water to rinse wort from the spent grains

This sparge water mixes with the strong worts to dilute the sparged worts.

Question 4

What is the relationship between sparge volume and soluble extract in spent grain?

Answer 4

A certain sparge volume is needed to ensure minimal soluble extract remains in the spent grain

The specific sparge volume varies with the separation device used.

Question 5

What determines the resultant wort strength in the kettle?

Answer 5

The volume of water used to obtain the extract

Higher water volume results in weaker kettle strength.

Question 6

If using 3 L/kg mash water and 3.5 L/kg sparge water, what is the kettle wort strength typically?

Answer 6

SG 1.061 or 15 ˚Plato

Terminating wort collection early can yield a higher kettle wort strength.

Question 7

What happens to kettle wort strength if weak worts are collected for future use?

Answer 7

It can be nearer to SG 1.070, or 17 ˚Plato

Recycling weak worts supports high gravity brewing.

Question 8

What is the typical pH range of the mash and strong worts?

Answer 8

pH 5.2-5.4

Sparge water may have a pH range of 6.5-7.5.

Question 9

What undesirable materials can dissolve from husks as wort pH increases?

Answer 9

Tannins and silica

These materials are detrimental to beer quality.

Question 10

What is the traditional method for terminating collection of weak worts?

Answer 10

Last runnings gravity check

This occurs at a strength of around SG 1.004-1.006, or 1.0-1.5 ˚Plato.

Question 11

What is the consequence of disposing of last runnings?

Answer 11

They are high in biological/chemical oxygen demand (BOD/COD)

Adjusting sparge water volume minimizes the volume of these last runnings.