Hey moi ! Je sais !Penn-Maen a écrit : Quelqu'un sait comment ça marche sur JB ?
J'utilise la formule de Palmer : http://howtobrew.com/book/section-3/the ... -additions
+ une variable d'ajustement configurable dans les paramètres du logiciel.
Hey moi ! Je sais !Penn-Maen a écrit : Quelqu'un sait comment ça marche sur JB ?
Hors en lisant le fameux traité, je comprends l'inversebastok a écrit :Ensuite, il y a un effet qu'ils appellent "slaking heat" qui décrit - grosso modo - la quantité d'énergie perdue à faire gonfler le gain. Cette perte d'énergie se traduit par une baisse de a T° de la maishe et se calcule avec la formule suivante
The fundamental fact with which we started was that when every care is taken to observe the initial temperature of mash made on an industrial scale in tho brewery, the observed temperature is always several degrees higher than the initial heat as calculated from the known temperatures and relative weights of the grist and water
Et d'ailleurs c'est aussi comme ça que Hush l'a introduit dans son premier message !Assuming that the whole of this slaking heat," or heat of hydration," as we then termed it, makes its influence felt in the hot mash, it is possible to determine the maximal rise of temperature of tho mash due to this cause over and above the temperature deduced from the mixing of so much malt and so much water at known temperatures.
I now propose to give formula which will supplant them and put the whole question on much more rational basis. The formula is as follows
(St° + RT°)/(S+R) + (1/2H /(S+R)) = I°
S : the specific heat of malt.
t° the temperature of the malt
R : weight of water corresponding to unit weight of malt.
T°: temperature of the water.
H : the slaking heat of the malt expressed in gram calorics Fahrenheit.
I° initial temperature of the mash.
J'étais parti dans l'idée que cette formule permettait de calculer la T° nécessaire à l'infusion initiale, mais il semble effectivement que ce soit le contraire.It will be noted that the first part of the above formula (St° + RT°)/(S+R) gives the mixing heat of the malt and water which would result if there were no evolution of heat due to the slaking effect
whilst the second expression 1/2H /(S+R) gives the number of degrees Fahrenheit which must be added for the slaking effect.
Ca ne laisse plus de doute quant au fait j'ai encore tout compris de traversBefore giving what believe to be the true explanation, it is desirable to examine little more closely into the causes of the rise of temperature when malt is mixed with water.
Nearly all organised substances, even when they contain no sensible pores or interstices, have the property of absorbing relatively large amount of water, which penetrates between the molecules of the substance and causes it to increase in volume. The forces exerted by this penetration of water are very great if measured by the external pressure necessary to prevent the increase of volume. For instance, the mechanical effects which are produced by merely m oistening wedges of dry wood driven into the face of solid rock are even at the present day often utilised in quarrying operations, and such methods were exclusively used by the ancient Egyptians for the quarrying of their largest monoliths.
This penetration by water of substances like cellular fibre and starch, etc., is known to botanists as imbibition," the water thus absorbed being called water of imbibition," convenient term perhaps, but one which merely expresses fact without suggesting any explanation. That "water of imbibition" is not merely held like water in sponge, but that, at any rate, some of it enters into combination with the absorbing substance, is shown in the first place by the evolution of heat which takes place, and, secondly, by the fact that the resulting volume of the substance plus that of the water absorbed is less than the sum of the original volumes.
Je suis plus à connerie de plus alors je me lanceHush a écrit :Bonjour,
Petite question au passage : Pensez vous que le degré d'hydratation du malt change en fonction de l'hygrométrie ambiante ?
Hush
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