It doesn’t seem like children in the schools today are really learning about what the ברכות on foods really mean. If parents want to be מחנך their children in the פירוש המילות of ברכות, at what age should they start?
At the earliest age possible. Now, at such an early age you won’t be able to teach them the details of what the words mean – they’re still too young. But tell them the ideas anyhow. For instance, you can tell your child, “Do you know how good it is to make a המוציא? Making a המוציא is a very big מצוה. You’re thanking Hashem for giving you this bread and Hashem is going to pay you back just for thanking Him. It’s like money in the bank.” Let him know that he’s talking to Hashem. That he’s not just saying words. Be מסביר it to him on his level. Later on, he’ll be able to take these thoughts and put them into the words of המוציא לחם מן הארץ.
How does bread come out of the earth? It’s a נס. It’s more of a נס than the מן that fell in the מדבר. At least the מן came out of the sky. But the wheat comes out of the earth. Nobody can really explain it. That large stalks of wheat should grow out of dirt! It’s a נס. So the יצר הרע tells you, “Well it’s the process of photosynthesis and the absorbing of nutrients from the dirt by the roots and so on.” So do you think that if you use words from the science books and explain the processes, that it makes it any less of a miracle?! Not at all! Studying those processes teaches you even more how many miracles are needed to make the wheat kernel grow. So you make sure to teach yourself to appreciate the המוציא and then you’ll be able to teach your children.
And therefore, you have to know that food is a tremendous miracle. And later, you’ll be able to explain it to him. But right now, he’s too young, so explain to him only that it’s a מצוה to make המוציא. And explain to him how great it is that Hashem gives us bread from the ground. And the child will feel it. Don’t think that he doesn’t understand it. Even the little children who seem to ignore what you’re saying, they’re human beings, so it’s going into their heads. They’ll remember what you said.
I remember what was said to me when I was two years old (The Rav was 90 years old when he gave this answer). I still remember. You’ll be surprised. It stays with you. Children don’t forget. So start as early as you can. It’s not a waste of time.