With the decrease of temperature, the sand particles in sugar tablets show a secondary distribution from less to more. There will be a layer of sand and two layers of skin on the cross section of the whole piece of brown sugar, which is also called "three-flower sugar". Sometimes, due to the influence of environmental temperature and mold shape, when the sugar layer is thick or high in sugar content or short-term multi-layer casting, it will also form three layers of sand and two layers of skin, commonly known as "five-flowered sugar", which is a rare product. Because the heat dissipation rates of the upper and lower layers of the casting model are sometimes inconsistent, the sand line is not necessarily in the middle.

However, the thickness of sugar skin of chip sugar is related to the variety, maturity, boiling time, temperature and sanding operation of sugarcane, and the specific performance is more complicated.

Is a piece of brown sugar without sand line necessarily fake? Not exactly. ① Some brown sugar sand lines are not open lines, but dark lines that are not easy to find. It seems that the sand line and the sugar peel are almost the same color, so it is difficult to tell them apart. In fact, it has hidden sand grains. This brown sugar is rich in molasses, which blocks the sand layer and makes it difficult for you to see the layers clearly. (2) Some pieces of sugar are relatively simple to make. Brown sugar will be cooled into blocks and form sand lines later, and there will be no sand lines. (3) In industrial production, if the nursing hall adopts the casting rapid cooling molding production process, the sand line is often not obvious. (4) No sand line can be seen in the pressed products of flake sugar or pink sugar made by secondary melting.

It can be said that if it is really a piece of brown sugar made by a manual workshop or a traditional craft, it should have the fragrance of sand thread and brown sugar, no odor and different colors. If it is a brown sugar block produced on an industrial scale by a regular manufacturer, the quality and efficacy will not be affected without sand lines.