Advice needed: controlled shrinkage of hand-knit wool hat

[sarahmck]

Here's the deal: We went to Scotland this Summer and my husband bought my son a hat.  I decided to buy some of the same wool and copy that hat for my husband.  But I am always lazy about gauge so I just increased the size of the hat based on the number of stitches in my son's hat and the comparative size of my son's and my husband's heads.  The problem is that I knit slightly more loosely than the woman who knit DS's hat and now DH's is too big.  Not crazily too big, though.

I haven't done the finishing and could just rip the entire thing out and start again.  Or I could sew it up and try to shrink it.  If the latter option would work that would of course be my preference since it would be easier and would make the hat even warmer.  My husband likes his hats super duper warm.

It's made of pure wool (100% North Ronaldsay wool -- those are sheep that eat only seaweed and it is supposed to add some wonderful quality of warmth or water repelence or something to the wool).  It's very unprocessed.  Pretty much just off the sheep and spun.

Should I try to shrink it?  How?  FYI, I have a European front-loading washing machine.

[sarahmck]

Anyone have any ideas for me?

[lapoli]

You could try to felt it by hand so you could keep an eye on shrinkage.  Some of the stitch definition would be lost, but it would save you having to reknit the entire hat.

[K'sMama]

Fill a pan with HOT, HOT water and another with ice cold water.  You can use your hands or a spoon to stir.  Put in the hot water and agitate a bit, take out and put into the cold water.  Keep repeating (with the agitating while in hot water), until it felts to the desired size.  I've done this before and it seemed to work really well - but it does take some time.

[mommy2maya]

I say to rip and knit tighter.  I would not trust it to felt properly.  Also, if it is very unprocessed it might not felt easily at all due to a large amount of natural lanolin