Just like every other 18th-century source I've seen on malting, the author wasn't very keen on wood as a fuel. In particular because of the horrible smoky tang it gave to the finished beer.
Of the drying of malt.
There is a dispute among malsters, about the thickness the malt should lie upon the hair cloth for drying. Our ancestors spread it very thin, they rarely let it lie at more than three inches deep : our late improvers, as they call themselves, lay it fix inches or more; but this is a great error. About four inches is a proper thickness: in this manner a space of fifteen foot square will dry two quarters of malt. It is not to lie all the time quiet. It must be turned upon the hair cloth as upon the floor, more or less, according to the nature of the fire, and the time intended to be allowed. If the fire be gentle, and 'tis a pale malt, that is to have ten or twelve hours on the hair cloth, once in four hours is very well for the turning: if it be a kind that must dry quicker, once in two hours will be a proper method : observing to keep a clean bottom. When the malt is sufficiently dried, it must be thrown off from the kiln to the floor, and spread thin and wide. in an airy place, that it may cool. Then it is finished and fit for use.
There is not, in all the common arts of life, any that requires so nice a caution as the making of malt. The time mull be considered : three weeks is a moderate allowance, often it will take much longer. As different lengths of time are required for drying malt, there have been invented various ways of doing it. The iron-plate frame, and the tile frame, both full of small holes, are esteemed by many; others prefer the brass-wire and others the iron-wire frame ; and others the hair cloth: the husbandman is not to give his voice in favour of any one of these in general terms ; but to consider the use it is intended to answer : the nature of the malt to be dried is a material consideration, for that kind will do for one that will not for another; and when the most expeditious can be used, without hurt, there is something in the saving of fewel. Those which do with the least fewel are the iron-plate frame and the tile frame : they were invented for this purpose, and are a ready and cheap method. They dry the brown malts very well, but they will not answer for the pale.
None of the methods heat the malt so violently as these, the corns often jump like parched pease, and crack: but they get -a fine brown. It is a cheap way ; but let the farmer fee he is not deceived in it, especially if he buy malt of this brown fort. The nature of it is to look dry, and it is not the worse for that; but those who fell it, frequently sprinkle water over it, and this makes it swell up vastly. 'Tis fairer to the eye, but this takes away a great deal of its sweetness.
People find the Brown malt dried this way apt to spoil in keeping : but they accuse the machine, when the malsters are in fault: all the damage is owing to the sprinkling water over it; this subjects it to decay in keeping. Brown malt, dried on one of these frames, will keep as well as any, if it be spread to cool as soon as made, and no tricks be played with it. All the damage it is subject to is, contracting something of a bitterness by burning ; but this is owing to the carelessness of the maker, more than the fault of the frame.
The carelessness of some, and the tricks of others, have turned these methods of the plate and tile frame out of fashion, but without any real cause. They are fit only for brown malts, but in a fair and proper management they dry these as well as any other of the methods, and much cheaper.
The wire frame comes next after the plate and tile ones, and now is generally used in their (lead. This dries the malt more gently and leisurely; but there is some difficulty in the turning it, and cleaning the bottom.
Of all the methods the plain and simple hair cloth is the best for the finest malts. A flow fire under this dries it very gradually and equally, it is easily turned as is required, and when it is done there is no difficulty in getting it out, for 'tis only turning it at once and all is clean.
Of the fuel to be used in drying malt.
The principal kinds of fuel are five: 1. Coak; 2. Welch- coal ; 3. Straw ; 4. Wood ; and 5. Dry fern or brakes. What is to be done by this fuel is to dry the malt, and nothing more : no flavour is required from it, and therefore the purer the fire is, and the cleaner the malt is dried by it the better. All smoak is wrong; and therefore all those fuels that yield a great deal of smoak, are to be rejected in the drying the nice malts.
Fern is a very bad fuel for this use : and at first fight a person might join wood and straw under the fame denomination, because of the quantity of smoak, but there is in this a difference. All smoak is an enemy to malt; but there are varieties in the taste and flavour of the smoak of different materials. The smoak of fern is not only plentiful, but of a very ill hogoe, which it will communicate to the malt. And the smoak of straw, though almost as plentiful as that of fern, is so sweet, that it scarce does any damage. The smoak of wood is of a middle nature.
Dividing our fuel into two general kinds ; the coak and welch coal being the best, and the straw, wood, and fern the inferior : the straw is the best of these, the wood the second, and the fern worst.
There never can be a necessity of using fern, therefore it ought wholly to be excluded : wood may always be had, and must be better than fern ; and for some of the ordinary malts it is a cheap fuel, and answers well. Straw, with good management, may he made to do for any but the very best and nicest kinds. With respect to the other two coak is the best; but the other is very good.
We advise the husbandman to use coak, if it is to be had ; but let him fee that it be good and well made: for otherwise the the inferior fuels may do better. Fine coak is made of large pit coal charr'd, or burnt to a cinder. It is to be burnt till all the ill smell is consumed, and no smoak rises; and in this condition it makes the steadiest and the sweetest fire of any fuel whatever. It is a common negligence to char this coal imperfectly, but the husbandman who dries his own malt should examine strictly into it; for one smoaky piece will do vast damage. He may fee this by the eye, for there is a particular dry aspect which coak has when well burnt, that is wanting in such as has any of its gross parts remaining.
The next to pure coak is welch coal: this is called by many culm. It is a fine sweet coal dug naturally out of the grounds It comes in thin fleaky pieces, and burns to white ashes with a little flame, and no smoak. This brings it nearer to the nature of coak, but it is not altogether so pure : however, it is cheaper in many places, and for all but the fine malts will very well answer.
Let the farmer, if he have convenience, dry his own malt, for out of this variety of materials it is possible the malster may chuse the worst: in some places it will not be worth while, because every thing must be built for it, and that the farmer may not think this proper, when he has a small family: but in other places most of the conveniences will be ready. In the hop countries the fame kiln that dries hops will dry malt ; and so on many other occasions; and wherever it can be done 'tis much best at home. As to a little expence, let him consider 'tis a thing for which there is a constant demand. I shall offend the malsters; but I must add, that if he knew their practices as well as I do, he would fee more reasons than are here set down for doing his business himself.
Source: "A Compleat Body Of Husbandry" by Thomas Hale, 1758, pages 316 - 319
If you're good I'll post the section on brewing from the book tomorrow.