If you are going to use a buttermilk substitute then add the lemon juice
to the milk and let it sit for 15 minutes

Meanwhile preheat the oven to 425 degrees.

Here is a common Whole Wheat pastry flour that you can buy.
There are other brands as well that work. Pastry flour is a soft wheat
and is typical of the flour that was grown in Ireland during the mid 1800's.
You can use half whole wheat flour and half All purpose flour if you can't
find the Whole wheat pastry.

Blend your dry ingredients together.
To get a lighter product sift them together.

Mix in the milk and blend till you get a nice firm dough ball.
if it is too sticky add a tablespoon more flour. It shouldn't stick to your hands.

Shape the dough into a circle about 2 inches thick and make a
Cross in the dough like so with the back of a large knife.

I am using a large Dutch Oven here to put my dough in.
This works well because the thick bottom keeps an even
temperature so the bottom crust doesn't get burned.
The covered chamber creates a nice uniform heat as well so the whole loaf cooks evenly. This is also how the housewife in Ireland origionally would cook this over an open fire.

I put this in the oven covered and set the timer for 20 minutes.
After 20 minutes I turn down the heat and uncover the bread and cook for another 10 minutes.

Here is the baked soda bread.

You will get a nice tap tap on the bottom crust when it is done

Wrap the soda bread in a towel for a bit. this absorbs some of the soda flavor and keeps it warm. Moisten the towel a bit to soften the crust a little if you want.