You are confusing Meiruach (or more generally, Gemar Melakha -- finishing the labor) and Keva' (establishment).
When one picks produce owned by a Jew in Israel, he is allowed to snack on it (אכילת עראי) even before tithing it until he finishes his work on the harvest (גמר מלאכה, such as your example of smoothing the piles) if he is planning on selling the crop. If he intends to keep it, then there are 6 ways the produce is established to be tithed (נקבע למעשר) after the harvest is done: bringing it into his house, separating Terumah from it, selling it, cooking it, pickling it, or trying to eat it on Shabbat. After one of those things happens, he can't even snack on the food before tithing it. (Rambam Maaserot 3:1-3)
The rule of "bringing it into your house" only applies if you bring it through a main doorway, not if you pass it in through the window. So if you wanted to avoid tithing, you could bring your produce into your house in a non-standard way and then only snack on it raw. The Gemara in Gittin (81a) praises the early generations who brought their produce home the normal way in order to establish it to be tithed, unlike the lowly later generations who would bring their produce home via the roof in order to skip out on tithing.