Here, we describe instructions for the assembly of an array of miniature (20-mL) chemostats or “ministats” built from relatively inexpensive off-the-shelf parts. In experiments with yeast cultures, we have observed reproducibility in cellular physiology, gene expression patterns, and evolutionary outcomes with different ministats as well as between ministats and commercial large-volume platforms. Growth in continuous culture is a primary means for the characterization of yeast steady-state physiology, competition between strains, and long-term evolution experiments. We hope that these relatively inexpensive and high-throughput devices make the advantages of continuous culture growth more accessible to researchers.