The evils of coloured malt

Here's on odd passage on the evils of coloured malt

"Now as to the Complexion or Colour of Mault, White is the best because most Natural, and therefore in all Preparations and Operations you ought, as near as possible you can, to maintain the Natural Complexion of the thing, for the tincture ariseth, and proceeds from the fine Spirits and essential Virtues; therefore, if in your order of making Mault you alter and change the Colour, you then also change its Virtues, and make the Drink of another Nature and Operation; for all redness, or high colour in Drink proceeds from some violence done to the fine Spirits and fine Virtues in the preparation, for the Colour is a stranger to the Nature of that Grain, and it shows that the fierce Spirits and hot Vapours of the Fire have as it were transmitted or changed the mild friendly, soft Virtues and Qualities of the Mault, into its own fiery Nature; force not Nature therefore out of her way, nor change the Form, for then the inward life and good Qualities of that thing are in danger, for the fierce raging Spirits of the Fire, and Essences thereof, do never depart from such parched high dried Mault, but do always remain, from whence the Drink made thereof receives its high bloody Colour, which most ignorant People cry up and admire as a Virtue of good Quality, but the contrary is to be understood, and nothing in Mault is a greater Vice or Evil, and the Drink made thereof, together with its long Boyling with Hops, do seldom fail to wound the Health of the Drinkers thereof; its natural Operation in the Body, is to heat the Blood, destroying the Appetite, obstructs the Stomach, sending gross dulling Fumes into the Head. Therefore if you have Wisdom and understanding of Nature, remember, that the nearer you come to Nature, and the more you imitate her, the nearer you are to the Truth."
[Thomas Tryon, The Art of Brewing, 1691]

Took things seriously in the old days, didn't they?