The method of baking which has been described above is known as the off-hand or straight dough method. It possesses the merit of rapidity and simplicity, but it is said by experts that it does not yield the best quality of bread from certain flours. Perhaps the commonest variation is that known as the sponge and dough method, which is carried out as follows. As before, the requisite amount of flour is weighed out into the mixing trough, and a depression made in it for the reception of the water and yeast. These are mixed together in the proper proportions, enough being taken to make a thick cream with about one quarter of the flour. This mixture is now poured into the depression in the flour, and enough of the surrounding flour stirred into it to make a thick cream or sponge as it is called. At the same time a small quantity of salt is added to the mixture. The sponge is allowed to ferment for some hours, being kept warm as in the former method. As soon as the time allowed for the fermentation of the sponge has elapsed, more water is added, so that the whole or nearly the whole of the flour can be worked up into dough. This dough is immediately scaled and moulded into loaves, which after being allowed to prove or rise for some time are baked as before. This method is used for flours which do not yield good bread when they are submitted to long fermentation. In such cases the mellow flours, which will only stand a very short fermentation, are first weighed out into the mixing trough, and a depression made in the mass of flour into which a quantity of strong flour which can be fermented safely for a long time is added. It is this last addition which is mixed up into the sponge to undergo the long preliminary fermentation. The rest of the flour is mixed in after this first fermentation is over, so that it is only subjected to the comparatively slight fermentation which goes on in the final process of proving.