DIY mash basket from 400 micron stainless mesh

[Gruel]

Unfortunately my 5 gallon brewing kettles are only 11" ID, so I can't use the very nice 13" stainless mesh baskets recently advertised (Stainless steel basket for BIAB brewing- cheap! ).

Therefore I ordered 5 feet of 12" 40 mesh (about 400 micrometer) 304L stainless mesh and some 1/8" 304L bars from McMasterCarr, and made a basket myself. Today I used it for the first time for brewing, and it worked very well. Much easier for stirring and cleanup, and a lot less messy than using a brewing bag. The only problem in manufacturing was drilling holes into the stainless bars for riveting. I went through two 3/16" cobalt drill bits until I decided that 3/32" rivets will be good enough. I also reduced the number of rivets attaching the mesh to the steel bar structure a lot from my initial plans, so in retrospect one or two 3/32" cobalt bits would probably have been enough for the whole structure.
It's a 9" tall 11" diameter basket, made entirely from 400 micrometer stainless mesh (bottom and sides); the bottom disk was cut from 12" wide material, same as the sides. I bent the disk edge up, using one of the kettles as a template, and then riveted everything together. I used the one perfect edge (the other edge was also very nice, but only one was perfect) of the material to form the bottom edge of the cylindrical sides; it sits snug enough against the bottom disk so that no grains got through, with rivets on about a 2" spacing.
The cylinder joint is finished with a double overlap ( both ends bent back on themselves) to avoid any exposed raw mesh edge. The top edge is folded inwards twice, again to avoid any exposed edge; folding outwards would have been better, but I wanted to finish the cylinder seam first, and after that folding outwards on a relatively small diameter cylinder didn't seem like a good idea.

Here are some pics:

McMasterCarr material list:

Line Product Ordered Shipped Balance Price Total 1 9241T22 Wire Cloth, 304 Stainless Steel, 40 x 40 Mesh, 0.0185" Opening, 1 Foot x 5 Feet 1 Each 1 0 24.43 Each 24.43 2 8992K113 Multipurpose 304 Stainless Steel Bar, 1/8" Thick, 1/2" Wide, Hot Rolled, 3 Feet Long 4 Each 4 0 6.28 Each 25.1

Buying the ready-made baskets would have been cheaper (drill bits are expensive at Home Depot!), and certainly more convenient, but since they don't fit, that was not an option.

 

[Gruel]

In the mean time I brewed 5 gallons of Weissbier and 5 gallons of Pils with this basket. For the Pils I got ambitious, and tried sparging with wort recirculation through the grain in the already raised basket. All went well, until the basket sprang a tiny leak near the bottom, of course on the side facing away. What a mess! Major cleanup of wort from the stove top. Luckily nothing had burned in yet.

So I either need to suspend the basket a bit lower inside the kettle, or fabricate a shield to go around for sparging. Otherwise the recirculation worked very well; the trick to not get any air sucked in at the pump connections (which then foams up the wort) is to keep the pump under water. Since the max temperature for the pump I was using is 60C, I kept it in a separate pot of cold water.

 

[Gruel]

Update: fabricated a shield (and new support brackets to replace those metal bars in the last pic above, while I was at it) for the grain basket. Recirculation worked great this time (wheat beer #4 for this year). It takes a long time though until the wort is clear.