Bale Grist Mill

Serendipity As we passed the Bale Grist Mill while travelling along the Napa Valley Highway Sally saw that the big waterwheel was turning, so we stopped to investigate, even though we had been told that the mill was closed. Sure enough the mill was open, as a group of school children were being shown around. We were fortunate enough to be invited to tag along with them. The tour was fascinating. The grist mill is quite large, so all the mechanical processes could be seen easily. We followed the energy path from stream to mill stones. The 36ft diameter wheel is an overshot, so the water flows over the top of the wheel, using its weight to drive the wheel (as opposed the an undershot wheel which uses the speed of the water to turn it). It was surprising how little water was need to drive the mill. The wheel is attached to a shaft which transfers the moving energy to the rest of the mill. There were a couple of take off points so that the energy could be used to move grain round the mill. Interesting were the vertical bands with small pockets attached to them, which were used to raise (or elevate) the grist (which is wheat which has been separated from the chaff) from the ground up to the hoppers used to feed the mill. Once lifted there is machinery to separate the grist from grit and weeds. The mill itself is composed of two granite mill stones dressed with an accuracy of less than a millimeter. The 1100 lb bottom stone rotates at about 200 r.p.m. The mill stones should never actually touch each other, so the corn/wheat is milled (cut up) rather than ground, so the top stone must be accurately placed, using a ring, or 'eye' on to a small shaft, called, for some reason 'The Cock', when the eye is correctly placed then the top stone is then centred on to the rotating lower stone, this is known as being 'cockeyed', strangely we now use the term in a reversal of its original meaning . The mill will produce a variety of flour grades as it works, though the miller has some control over the flour as the top stone can be raised and lowered to roughly determine the grade of flour produced. However as the stone is encased the only way to tell just how big the gap is is to send a small amount of grist through and feel the size of the flour produced, this is done by rubbing the flour between fore finger and thumb, hence the saying 'rule of thumb' At its lowest it will produce finer flour. Too low and the mill stones make contact and the heat of friction will burn the flour, making a smell,, rendering that batch of flour useless, hence the miller must keep his 'nose to the grindstone' to ensure that it is not burnt. The ungraded flour is then elevated again by the 'Run of the mill' elevator (referring to ungraded, or generalised flour being run right through the mill), to be separated into four grades of flour. Fine, Fair, Middlin and bran. The most average flour grade became known as 'fair to middlin'. Once graded the flour is then dropped back down to the ground floor to be bagged. Interestingly milling is a continous process, with a large amount of grain being held in the hoppers, so the grain a farmer brings in is not necessarily used to make the flour he gets out! The miller will assess the farmers grain for quality and ratio of grain to grit/weeds and tell him the % of flour that he will get back, which leaves a lot of room for diasgreements I would think. We learned all this as Jim the miller showed us all round the mill, with the belts, shafts and gears clanking away quietly in the background, finally he actually used the mill to produce some pollenta (a course corn flour). It was a fascinating process and we really enjoyed just being there, watching and learning.

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