Bourne Archive: Muspratt: Hops

The Bourne Archive

Muspratt’s Chemistry, Theoretical, Practical & Analytical (ca. 1859)

Extracts Concerning Beer, 4: Hops.

The web pages intended to be linked from this introduction are from an article on brewing, under the heading ‘Beer’. The original article is presented here in several web pages, respectively dealing with: 1, barley; 2, malting; 3, water; 4, hops; 5, grinding malt; 6, mashing; 7, saccharometry; 8, boiling; 9, cooling; 10, fermentation; 11, cleansing.

Vol. 1. pp. 245-247.

HOPS.—The wort, as prepared from malt, is unpalatable and viscous; and to bring it into a potable ¹ state, and ensure the permanence of its virtues, it has been found necessary to make some addition to it previous to fermentation. This effect is best produced by means of hops, the properties of which, and the characteristics by which they may be selected, will now be concisely pointed out.

Hops are the strobiles or catkins of humulus lupulus, a diœcious plant belonging to the natural order Urticaceæ, the culture of which was first introduced into England from Flanders in the reign of HENRY VIII.

The various parts of the hop are, scales, nuts, and lupulinic grains or glands. The scales are the enlarged and persistent bracts enclosing the nuts, which are small, hard, nearly globular, and covered with aromatic superficial glands, commonly termed yellow powder or lupulin. These form the most important part of the strobiles.

Dry hops ought to yield about one-sixth of these grains. They are usually mingled with sand.

PEREIRA ² says they are rounded, of a cellular texture, golden-yellow colored, somewhat transparent, and are sessile, or nearly so.

The common centre around which the cells are arranged has been denominated the hilum. They lose their spherical form by exsiccation, and, when placed in water, give out an immense number of minute globules. Under different circumstances they become ruptured, allowing and inner envelope to escape. TURPIN ³ states that they consist of two vesicles, one eviscerating the other, the interior containing globules, aromatic oil, and a gas, and affirms that, in the bubbles of discharged gas, a large number of crystals are formed.

The scales and lupulinic grains have been analyzed by PAYEN, CHEVALLIER ⁴, and PELLETAN ⁵, with the following results:—

LUPULINIC GRAINS.
	Centesimally ⁶ Represented.
Volatile oil, ………………………………………….	2.00
Bitter principle—lupulin, ……………………..	10.30
Resin, ………………………………………………….	55.00
Lignin, ………………………………………………..	32.00
Fatty, astringent, and gummy matters, osmazom ⁷, malic and carbonic acids, salts, as malate of lime ⁸, acetate of ammonia, chloride of potassium, sulphate of potassa, et cetera, …………………….......	Traces
Loss, ……………………………………………………	_00.70_
	100.00

The scales were found to consist of astringent matter, inert coloring matter, chlorophyll, gum, lignin, and salts of potassa, lime, and ammonia, containing acetic, hydrochloric, sulphuric, nitric, and other acids.

The scales usually have lupulinic matter adhering, from which it is almost impossible to free them.

Dr. ives also examined the lupulinic grains, and obtained:—

	Centesimally Represented.
Tannin, …………	4.16
Extractive, …….	8.33
Bitter principle,	9.16
Wax, ……………..	10.00
Resin, ……………	30.00
Lignin, ………….	38.33
Loss, ……………..	_00.02_
	100.00

The volatile oil exists in the lupulinic grains, and is procured by distilling them or the hops with water. It has a yellowish color, an acrid taste, and its color is similar to that of the strobiles. It is partially soluble in water, but more so in alcohol and ether. It has a specific gravity of 0.910, becomes resinified by keeping, and is said to have a narcotic influence on the system. The water which distils over with the oil contains acetate of ammonia.

Dr. RUDOLPH WAGNER ⁹ has lately published an interesting paper upon the oil of hops, and as his results are different from all hitherto obtained, a notice of them may be serviceable to the brewer. Dr. WAGNER distilled the oil from fresh hops with water. It constituted about eight per cent. of the air-dried flowers. It possessed a clear brownish-yellow color, and had a strong odor of hops, and a slightly bitter taste analogous to thyme. Its specific gravity was 0.908 at 61° Fahr. It scarcely reddened litmus paper, and was very sparingly soluble in water, requiring more than six hundred times its weight for solution. It contained no sulphur. The oil, rendered anhydrous by distillation over fused chloride of calcium, partly evaporates at a temperature below the boiling point of water. It begins to boil at 257°, rising to 347°, where it remains stationary for some time, and at which temperature nearly one-sixth of the clear oil distils over. The portion passing over between 347° and 437°, and constituting one-half of the oil, was also of a yellow color. The residue in the retort, about one-sixth of the quantity submitted to distillation, was brownish, and like turpentine. It is therefore, evident that oil of hops is a mixture of oils. The crude oil does not give, with ammonia-silver, a metallic mirror. It is therefore not an aldehyde. When mixed with alcohol-potassa, it becomes brown, and when distilled affords alcohol, and an oil having the odor of rosemary.

After the greatest part of oil and spirit has distilled over, a violent action takes place, hydrogen is evolved, and carbonate of potassa, mixed with a potassa salt of a volatile fatty acid, remains; the latter, when decomposed with diluted sulphuric acid, evolves an odor indicating the presence of caprylic and pelargonic acids.

From PAYEN and CHEVALLIER’S analyses and report, the oil was supposed to resemble oils of mustard, asafœtida, et cetera, and to belong to the ethereal oils containing sulphur; that it dissolved largely in water, and on this account preserved the beer, and that it acted partly as a narcotic in beer and hops.

According to WAGNER the oil is isomeric with Borneo camphor, oils of cajeput and bergamot, and with the aldehyde of campholic acid. This chemist, in conjunction with Dr. BIBRA ¹⁰, made experiments upon animals, to ascertain whether the oil of hops acted as a narcotic; they found that it had no such action.

The bitter principle of hops, or lupulin, may be obtained by treating the aqueous extract of lupulinic grains, combined with a little lime, with alcohol. The solution thus formed is to be evaporated, the mass treated with water, and the solution again boiled to dryness. The residue, on washing with ether, is lupulin. It is uncrystallizable, white, very bitter, soluble in twenty parts of water, very soluble in alcohol, and in ether slightly so. The aqueous solution froths on agitation, and, according to PEREIRA, gives no precipitate with tincture of galls or acetate of lead. Lupulin contains no nitrogen. It is devoid of the narcotic properties of the oil, and is said to have caused loss of appetite, and diminished digestive power, when administered in small doses.

The tannin ¹¹ serves, in brewing, to precipitate the nitrogenised or albuminous matter ¹² of the barley, and, therefore, assists clarification.

The resin has a golden-yellow color, becomes orange-yellow on exposure to the air, dissolves both in alcohol and ether, and is apparently the oil changed by oxidation.

A decoction of hops freely reddens litmus, owing to free acid being present; sulphuric and tannic acids, and also lime, may be detected in it even by those who have little experience in analysis.

Dr. IVES first applied the term lupulin to the pollen, or, as it is technically denominated, the condition of the hop; the name has been applied since, however, to the bitter extract of the scales.

The Editor ¹³ found that hops, in the usual marketable state, lose between eleven and twelve per cent when dried at 212° Fahr., and leave, on burning, from five to eight per cent. of ash.

Mr. HOLDEN obtained, on incinerating a good sample of hops, 7.708 per cent. of inorganic residue.

The drying of the hop constitutes a very important part of its management; it is performed in kilns, generally of very unscientific construction, and apparently capable of great improvement.

In Sussex, these are termed oast-houses. The heat imparted by the fire in drying is of great importance, and should in no instance exceed 119° or 120° Fahr.

The farina or pollen which falls through the hair-cloth, or wire, in the course of desiccation, is a valuable article, and is designated hop-dust. If care is taken that no particles of fire fall into the kiln-pit, and the hop-dust be frequently removed therefrom, so as to insure its freedom from extraneous matter, it is scarcely less useful to the brewer than the hops themselves. One pound of the dust is equal to four times the quantity of the strobiles. In dark-colored or common beer, a small amount might always be used without injury.

According to BRANDE ¹⁴, in order to give the hops a good color, they are subjected to fumigation with sulphurous acid; after this process they are packed into sacks or pockets, and subjected to great pressure, so as to prevent access of air, and their consequent deterioration.

Qualities.—The medicinal properties of hops are numerous. The odorous emanations arising from them possess marked narcotic properties. Hence a pillow of the cones has often been prescribed to promote sleep, in cases where the administration of opium could not be effected, or would have been objectionable. Both infusion and tincture of hops are mild and agreeable aromatic tonics. They sometimes manifest diuretic, or, when the skin is kept warm, sudorific qualities. Their sedative, soporific, and anodyne properties are very uncertain.

The lupulinic grains are aromatic and tonic, and appear to be soothing, tranquillizing, and slightly sedative and soporific. Hops have been given internally to relieve restlessness consequent upon exhaustion or fatigue, to induce sleep in the wakefulness of mania and other maladies, to calm nervous irritation, and to relieve pain in gout and rheumatism. They have also been applied, topically, in the form of a fomentation or poultice, as a resolvent ¹⁵ of discutient ¹⁶ in painful swellings or tumors.—Pereira.

The Editor does not attach much importance to the assertion that hops are narcotic, and that their influence upon the system is wonderful, especially when they are used in pillows, as he considers that the imagination plays a most important part in all such matters,—vide spirit-rapping, table-turning ¹⁷, et cetera.

The properties of hops in brewing are important, but may be given in a few words.

All the medical qualities are to some degree exerted by the liquors in which they have been employed. They render the beer more stimulant and cordial, and the bitter principle overcomes the disagreeable sweetness arising from the malt, and which, if unneutralized, might be offensive, if not injurious, to persons having weak digestive organs.

The stimulating and strengthening qualities found in bitter beer, may be said to be owing almost entirely to the hops.

They are slightly anti-fermentive, and but for the use of them in brewing, the ale produced would soon undergo the acetous fermentation, or, in popular language, become sour.

Selection.—The flavour of the Golding or Farnham hops is rich and delicate, but the plant is one of the most tender cultivated, and the crop is uncertain. They are the heaviest, consequently possessing the greatest amount of farina or condition, and the flower is the most diminutive.

The Flemish plant produces a large flower, often three inches in length, and is considered as one of the most hardy kinds. It is productive but of light weight, and is ill flavoured.

In the districts of Kent and Sussex, the Canterbury grape, a very good and useful hop in the trade, is much cultivated.

Other varieties are produced in various parts of the country, especially in a district called North Clay ¹⁸, in Nottinghamshire. These hops are strong, and fit only for porter brewing, even when mellowed by age. An extract from TIZARD as to the various estimates of the value of each variety may not be unacceptable.

Farnhams, he states, are in high repute, though not worth the price the brewer usually gives for them, unless the proximity of his residence be a consideration in their favor. The North Clays are the rankest in taste ¹⁹, and fetch a better price with a certain class of buyers than those from Kent, though not generally so high as the Farnham variety. Those grown in the neighborhood of Canterbury have been much prized for their superiority, but that is not invariable. The produce of the county of Kent, though pre-eminent both for strength and flavour, differs according to soil and season, which are not always adapted to each other. The Wealds are celebrated in some of the Southern and Midland counties, but in those more north, as Cheshire and Lancashire, the Worcesters are preferred for their mildness, and for the grateful sensation they yield; some use a few Sussex or Kents with them, but most brewers in the counties just referred to, reject the growth of Kent as unpleasing to their customers.

But, however good the produce of any district may be in general, it must not be supposed that there are no bad samples of those varieties.

Such bags should be chosen as are heaviest, because it is the farina which gives weight, and hops which lose part of it from fine weather or over-ripeness, in picking or turning on the oast, will considerable diminish in gravity.

They should feel clammy when handled, should be uniform in color, without greenish particles in the flower, and full of hard seeds, and farina or condition.

Mould may be discovered in the sample by the strig or flower being partly bare of leaf. Particular attention must also be paid to crust, proceeding from damp or bad keeping, as it injures the quality more than age.

From the uncertainty of the seasons, the hop is an article liable to considerable fluctuations in its commercial value. The duty on hops is twopence per pound ²⁰, with five per cent. additional; this levy does not extend to Ireland. Latterly, foreign hops have been used to a considerable extent by many brewers, even in the manufacture of the finest ales; they do not, however, possess that richness of flavor so characteristic of the English growth, and hence they are never used alone, but mixed with English hops in different proportions, varying from a third to a sixth of the latter. This mixture is found to answer in a manner as well as if the entire were of home growth, especially where bitterness is required to a considerable extent, and only a moderate portion of the flavor.

The foreign hops imported into Great Britain in 1852 were 34,622 pounds ²¹, whilst in 1853 the quantity amounted to 4,739,307 pounds ²².

The following table shows the number of pounds weight of hops which paid duty in England during the years 1848 to 1853, inclusive, the amount of duty levied thereon, and the number of acres of land under the crop, during these years:—

Year.		Acres.		Pounds of hops.	Amount of duty.
1848	….	49,232	….	44,343,984 ….	£388,007	3	8
1849	….	42,798	….	16,650,914 ….	145,693	4	9
1850	….	43,125	….	48,537,669 ….	424,702	3	0
1851	….	43,242	….	27,042,919 ….	236,623	1	10
1852	….	46,157	….	51,102,494 ….	447,144	8	1¾
1853	….	49,367	….	31,751,693 ….	277,824	16	9

Commentary.

1. ^ Drinkable (OED).

2. ^ This is probably Jonathan Pereira.

3. ^ Possibly Pierre Jean François Turpin.

4. ^ Possibly François Fulgis Chevallier (French Wikipedia).

5. ^ Possibly Pierre Peleton (French Wikipedia).

6. ^ Centesimally represented = represented as a percentage.

7. ^ Osmazome, the chemical or group of chemicals thought to produce a meaty taste or smell (paraphrasing OED). Wikipedia discusses the subject under the heading of umami.

8. ^ Probably Calcium malate. See Dietary calcium supplements — Calcium chelates.

9. ^ Probably Professor Wagner of Erlangen.

10. ^ Probably Ernst von Bibra.

11. ^ Muspratt discusses tannin with the subject of tanning leather. See also Wikipedia.

12. ^ Part of the endosperm. See also Albumin.

13. ^ Sheridan Muspratt.

14. ^ Probably William Thomas Brande of the Apothecaries’ Society and Royal Mint.

15. ^ ‘Having the power to resolve; causing solution’ (OED). In other words, in this case, clearing up the tumour.

16. ^ Having the quality of dissipating morbid matter; resolvent (OED).

With thanks to Wikipedia

17. ^ Muspratt was writing when popular Spiritualism was a growing social craze, developing from the 1840s, onward. The song, Spirit Rappings was published in 1853. He seems also, to have begun to catch onto the idea of auto-suggestion, a word which did not appear in the original OED, the relevant volume of which appeared in 1885 (OED Historical Introduction). In a modern (1987) supplement of that dictionary, the earliest note of it is dated 1890.

18. ^ North Clay is the modern name of area covered by the Domesday-period wapentake of Oswaldbeck, which lies on the west bank of the Trent, north of Littleborough, in north Nottinghamshire (Morris 28), with the Isle of Axholme to its north.

19. ^ The adjective ‘rank’ has a range of meanings arising from a basic idea of ‘strong’. Here Muspratt probably means that of all varieties, this has the least subtle flavour.

20. ^ 1/120^th of a pound sterling per pound weight.

21. ^ 15,704 Kg.

22. ^ 2,149,713 Kg.

See also A.C. Chapman’s 1905 monograph on hops.

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