This section is from the book "A Treatise On Flour, Yeast, Fermentation And Baking Together With RecipesFor Bread And Cakes", by Julius Emil Wihlfahrt. Also available from Amazon: A treatise on flour, yeast, fermentation and baking, together with recipes for bread and cakes.
This is the most dreaded bread disease and many bakers do not know the real cause of it. Years ago the cause of rope was ascribed to filth. It was then more common. The bakeries were, many of them, located in damp cellars and it required only excessive heat to develop rope.
Rope is a germ disease. The germs are most likely to develop during hot weather in bread that is not sufficiently fermented or not well baked. To make this point clearer, I might say that during extremely hot weather, especially on humid days, a dough heats up more than ordinarily during fermentation. Furthermore, the humidity lends the dough an additional amount of heat, which hastens fermentation with the results that the expansion of the same weight of carbonic acid gas is greater than on a cooler and less humid day. As this gas, which is necessarily produced during fermentation, is enveloped in a dough of higher temperature, it expands to a greater extent than its natural volume. In a word the dough becomes light without being ripe. When the baker turns a dough in this condition of immaturity, the bread will have a tendency to color too rapidly during baking, and consequently will, as a rule, be withdrawn from the oven without being sufficiently baked and containing too large an amount of moisture. Naturally it is also low in acidity and such a loaf, insufficiently fermented and insufficiently baked is most readily attacked by ropy germs. Too hot an oven would also have a tendency to bring about a similar condition. In all such cases I noted a premature mould appearing on the loaves as early as twenty-four hours after baking - before rope had developed. The percentage of acidity in a dough controls the premature moulding of bread as well as the development of rope.
Before bread can be ropy the germs or spores must be present in large quantities so as to have an opportunity to thrive and develop in the dough during fermentation. This proves that a bakery must be thoroughly infected with the germs or spores before rope can be developed in the bread.
Rope causes fine silvery threads in bread, which appear when the loaf is broken apart. Characteristics that accompany it are soft, wet, sticky and clammy crumb, a sort of foxy colored exterior, immature crust and a repelling odor. These characteristics are not present during the early stages and frequently do not develop until some twenty-four hours after the bread is baked.
The treatment for this dreaded disease is divided into two parts:
1st - Direct application to arrest the difficulty.
2nd - Sanitary measures to kill the germs and insure against a recurrence of the trouble.
The first part, arresting the disease, we will now discuss. I have had a good many cases under my care and treated them first by the direct application of organic acid, obtaining remarkably good results. I began by using lactic acid U. S. P. "Merck," one-tenth of one per cent of the weight of flour employed in doughing; that is one and six-tenths ounces of lactic acid for each 100 lbs. of flour used. I allowed the dough to ferment one-half hour longer than usual and by this method secured a loaf that did not differ materially from the regular bread to which the trade had been accustomed. I consider this very important.
The next step was to see that all stale returns of bread (manufactured before using lactic acid) were strictly kept from the premises. These return loaves were burned or destroyed absolutely in some other way.
We then proceeded to clean the bakery and utensils by whitewashing or painting the walls, cleaning the floor and utensils either with live steam or with a hot solution of boracic acid. When live steam is used it must be introduced through a steam hose with a suitable nozzle; the pressure should be 90 lbs. and the nozzle should touch the utensils and the floor.
After cleaning, the shop was secured air tight and fumigated; either by the use of 40% U. S. P. formaldehyde, using a 10% solution, by adding one part to nine parts of water and sprinkling same freely over the floors; or formaldehyde candles, free from sulphur, were used to effect satisfactory fumigation.
In shops where baking had to be conducted continuously from the beginning to the end of the week, we sprayed a moderate amount of formaldehyde around the bakery every day - as much as we could without having the fumes affect the workmen. A thorough fumigation was resorted to at the earliest opportunity the following Saturday.
After two or three days we reduced the amount of lactic acid by one-third; after another week we cut down the acid another one-third, and continued to employ this small quantity for two weeks more, or until we were absolutely sure that no stale returns from any source could be the means of reinfecting the bakery.
Do not overlook the necessity of thoroughly cleaning the interior of all your wagons and the importance of requesting your grocer customers to keep all bread boxes open after removal of bread, so as to give the boxes a good airing.
I have attempted to eliminate ropy bread by making the dough stiffer, using less sugar, giving the dough greater age, baking bread more thoroughly and cooling it rapidly. In addition, I applied sanitary measures by sterilizing utensils, whitewashing and fumigating. In a number of cases, excellent results were obtained in this way without the use of lactic acid, but other cases would not yield to this treatment. Probably the reason was that it is almost impossible to get a bakery airtight, so that by fumigation you will kill all the rope spores. These spores which produce the disease in bread must be subjected to fumigation for eight hours, so you see how difficult it is.
I wish to emphasize in the strongest possible terms that the application of lactic acid in proper proportions immediately and absolutely arrests the development of rope in bread. I also wish to emphasize that the necessary cleaning and sanitary measures must be promptly exercised to avoid a recurrence of the trouble. The use of lactic acid will not have an unfavorable result on the quality of the bread and the baker need have no fear about using it in the proper proportions.
I fully realize that the study of rope involves many principles, but I wish to state once more that the application of organic acids is not only the quickest but the only safe and immediate remedy when applied in connection with the necessary cleansing and disinfecting measures.
In referring to organic acids, I wish to state that lactic is to be preferred, but when it can not be obtained, acetic acid in the form of vinegar may be applied with satisfactory results. When using vinegar, I employed 1% of 90 grain vinegar to the weight of flour used in doughing. After two or three days application we reduced this to 3/4 of 1% and after a week to 1/2 of 1%, continuing to use this amount for at least two weeks more.
When vinegar is used to eliminate rope, there is bound to be a sour smell about the premises, but this disappears quickly after the baking and when vinegar is used in the proportions given no trace of sourness remains in the bread.
The use of vinegar, however, slightly affects the bloom and color of the crust; there is a paleness with an inclination to grey, which is not found when lactic acid is used. The inside of the loaf when vinegar is employed is whiter than usual. It would be perfectly safe for a baker experiencing an attack of rope to rely on the immediate application of vinegar, if he cannot obtain lactic acid or if for the sake of economy he prefers to use vinegar. The cost of vinegar would be approximately 3 cents for every 100 lbs. of flour and of lactic acid 8 cents for every 100 lbs. of flour.
I have experimented with smaller proportions of acids for a start and while laboratory tests show that these may be used, for practical purposes the proportions stated herein are the most satisfactory.
It has been stated that yeast may be at fault in propagating rope in bread. This idea was probably advanced before bakers knew the proper remedies for fighting rope, because there is no question but that organic acids, lactic or acetic (vinegar) will immediately check the trouble and all yeast has to be made in acidified media. In other words, yeast is manufactured in acid mashes and therefore cannot be infected by germs of rope.
To sum up; when the disease asserts itself, it is necessary to secure either lactic acid or vinegar immediately. Add it to the dough in the proper proportions by diluting it in the bulk of the water used. Dissolve salt and yeast separately in part of the water, add the salt solution to the bulk of the water containing the acid, next add sugar, milk and malt and finally the flour. Start to mix and after the machine is in operation for a few minutes, add the yeast. Allow the machine to mix for a couple of minutes more until the yeast has been thoroughly incorporated and then add the shortening.
In connection with this treatment, I wish to call your attention especially to the fact that I allow the dough a half hour more time for fermentation when lactic acid is used, whereas by the use of vinegar I allow the regular period of time for fermentation.
As a final precaution, I warn once more that all stale bread must be kept from the premises until one has the assurance that the disease no longer exists and is entirely eradicated, which fact must be corroborated by the actual condition of returns of stale bread.
Further, all bread wrapped in waxed paper must be thoroughly cooled before being wrapped, which naturally requires a longer time in hot weather than in cooler weather. Wrapping bread too hot in airtight packages alone can be the cause of generating ropy bread. All bread, including such that is sold without being wrapped, should be so situated after baking as to secure a rapid and complete cooling before wrapping or packing. When rope in bread has made its appearance it is well to make the dough a trifle stiffer and to secure a strong fermentation, as more ripeness and lightness of dough is necessary to obtain the best results.
Adherence to strict rules as set forth herein and energetic application to enforce the sanitary measures have given me immediate results in eliminating rope in bread. The sanitary measures are absolutely necessary, lest some of the spores may remain dormant about the bakery, which a subsequent spell of hot weather, either the same or the following summer may again develop into a sufficient amount of spores to cause a recurrence and an outbreak of new spores; in short, then the application of organic acids arrests the disease immediately. The application of proper sanitary measures eradicates the trouble.
The precaution against this trouble lies in making the doughs a trifle stiffer, allowing them to become very light on first rise before turning of dough by holding the ovens a trifle on the cool side to insure thorough baking and finally attend to the proper cooling of the bread before wrapping and packing. If this precaution if taken during extremely hot weather the chance for ropy bread is almost impossible. Remember an ounce of prevention is worth pounds of cure.