Lorenzo, ang siete viernes nga tuba is sieved or filtered for 7 days until there is no more precipitation which is the by-product of yeast and sugar (as explained by proddi). The remaining liquid is clear pale red in color that contains 10% alcohol with similar taste as white wine. During the Hacienda times, Friday night is usually drinking night because the next day is holiday. So they will consume their tuba usually on Fridays, which is Viernes in Spanish.
Making bahalina is like aging process where the siete viernes is preserved. You can ask Ginger or Kiamoy about this process as they are the authority. What I knew is that the containers should be filled to the brink, not allowing a space of air and then sealed it tightly, thus preventing aerobic bacteria from multiplying that cause acidity. To preserve the color, they will either store it in dark areas or burry it underground for a month or longer. This is what I know.
Balik ta sa balud or Bawd sa Binol-anon. Na puzzled ko ani nga word kung asa gikan ang root word ani. Sa among leksyon sa Engineering, ang among tawag sa Curve that represents changes in Frequency is called "Baud" which literally means wave in physics. This can also be used in sound or light frequency. I don't know if this word came to the Bisayan vocabulary or is Baud (physics) derived from polynesian/srivijayans who are masters of the waves.