Albert Barnes Commentary Exodus 1:14

"and they made their lives bitter with hard service, in mortar and in brick, and in all manner of service in the field, all their service, wherein they made them serve with rigor." — Exodus 1:14 (ASV)

The use of brick, common at all times in Egypt, was especially so under the 18th Dynasty. An exact representation of the whole process of brickmaking is given in a small temple at Thebes, erected by Tothmosis III, the fourth in descent from Amosis. Immense masses of brick are found at Belbeis, the modern capital of Sharkiya, that is, Goshen, and in the adjoining district.

All manner of service in the field – not merely agricultural labor, but probably the digging of canals and processes of irrigation, which are especially burdensome and unhealthy.