I have been cellaring fine California wines since the 70's and long ago drank up my mistakes. Now at 25 - 30 years, some have proved to be very age worthy and are outstanding. Keep in mind that many wines from the
70's were very ripe "monsters". Some have matured very well, and others had too much tannin and long ago dried out.You can find minute technical details about how such wines were made in the book "Great Winemakers of California" by Robert Benson, Capra Press, Santa Barbara 1977. The book likely is out of print, so you may have to go to a library to find it. Benson interviews many of the top wine makers, and gives their replies to his questions. A few of the wine makers were Martin Ray, Paul Draper, Andre Tchelistcheff, Warren Winiarski, Mike Grgich, Donn Chappellet, Jerry Luper, Joseph Heitz, Robert Mondavi, Richard Arrowood , etc. Many of these give details about if they add acid or not and what kind, if they use malo-lactic fermentation or not, what kind of yeast they use, what kind of wood they use, when and how they use SO2 or sulfites, and on and own. You will find a great variety of procedures. Some never add acid, some do only in hot years, etc. Some areas such as Napa seem more likely to need acid than some other areas.
I have pulled 3 remarkable California wines from the cellar to read the labels. The Freemark Abbey Edelwein Gold 1976 Johannisberg Riesling perhaps is the greatest Riesling ever made in California with no end in sight. It is about the richness of a fine German TBA. Residual Sugar is
16.4% and alcohol 10.5%. The sugar to acid balance is about the same as in a great Rheingau TBA. The Joseph Phelps Napa Valley Selected Late Harvest Johannisberger Riesling 1978 has 30% by weight of residual sugar, is 10% alcohol by volume, and had 48% by weight of sugar at harvest. Yet the acid to sweet balance is perfect. The Callaway 1977 Temecula "Sweet Nancy" Late Harvest Chenin Blanc has 10.7% by volume of alcohol, 9% residual sugar, and 0.9% total acidity by volume. It does not compare with the best late harvest Chenin Blancs from the Loire, but there is no doubt that it is a fine example of a late harvest Chenin Blanc that ages very well. I will not bother to detail the fine Monte Bello Cabernet Sauvignon from Ridge during this era. Most have lasted well, and several are outstanding and still will keep. I mention but a few examples. There are many others.The famous California microclimates in areas near the coast produce radically different growing conditions. It is nearly as if you had Bordeaux in one area, Burgundy a short distance away, and Morocco just a few miles further on. Those cold Pacific waters, valley orientations, and wind directions are responsible for this wild climate variation. Thus it is no surprise that very different techniques can be best for different regions.