Process for in vitro producing a cardiac organoid comprising a) providing cultivated pluripotent stem cells (PSC) in a suspension in a first culture medium, b) centrifuging the PSC in a first vessel having a U-shaped bottom to localize the PSC at the bottom of the first vessel, c) incubating the PSC localized at the bottom of the first vessel under the first medium under cell culture conditions, d) optionally removing the first medium from the PSC localized at the bottom of the first vessel, e) embedding the PSC within hydrogel, f) incubating the PSC embedded within the hydrogel for solidifying the hydrogel, g) covering the cells embedded in the solidified hydrogel with a second cell culture medium and incubating under cell culture conditions, h) removing the second medium from the cells and adding a third cell culture medium containing a first differentiation factor having activity to induce the WNT pathway and incubating under cell culture conditions for at least 6 h, i) removing the third medium from the cells and adding a fourth cell culture medium not containing a differentiation factor or containing an agent neutralizing the activity of the first differentiation factor, and incubating under cell culture conditions for at least 6 h, j) removing the medium from the cells and adding a fifth cell culture medium containing a second differentiation factor having activity to inhibit the WNT pathway and incubating under cell culture conditions for at least 1 d, k) removing the fifth medium from the cells and adding a sixth medium not containing insulin and not containing a differentiation factor having activity to induce or to inhibit the WNT pathway, and incubating under cell culture conditions for at least 1 d, l) removing the sixth medium from the cells and adding a seventh cell culture medium containing insulin and incubating under cell culture conditions for at least 1 d, m) and subsequently change the seventh medium for fresh cell culture medium at least every 2 d. a) providing cultivated pluripotent stem cells (PSC) in a suspension in a first culture medium, b) centrifuging the PSC in a first vessel having a U-shaped bottom to localize the PSC at the bottom of the first vessel, c) incubating the PSC localized at the bottom of the first vessel under the first medium under cell culture conditions, d) optionally removing the first medium from the PSC localized at the bottom of the first vessel, e) embedding the PSC within hydrogel, f) incubating the PSC embedded within the hydrogel for solidifying the hydrogel, g) covering the cells embedded in the solidified hydrogel with a second cell culture medium and incubating under cell culture conditions, h) removing the second medium from the cells and adding a third cell culture medium containing a first differentiation factor having activity to induce the WNT pathway and incubating under cell culture conditions for at least 6 h, i) removing the third medium from the cells and adding a fourth cell culture medium not containing a differentiation factor or containing an agent neutralizing the activity of the first differentiation factor, and incubating under cell culture conditions for at least 6 h, j) removing the medium from the cells and adding a fifth cell culture medium containing a second differentiation factor having activity to inhibit the WNT pathway and incubating under cell culture conditions for at least 1 d, k) removing the fifth medium from the cells and adding a sixth medium not containing insulin and not containing a differentiation factor having activity to induce or to inhibit the WNT pathway, and incubating under cell culture conditions for at least 1 d, l) removing the sixth medium from the cells and adding a seventh cell culture medium containing insulin and incubating under cell culture conditions for at least 1 d, m) and subsequently change the seventh medium for fresh cell culture medium at least every 2 d. <EOS>