It may seem somewhat improper to review a book by my wife, but hey, she asked me to do it and I'm being upfront about my "bias"!
With said bias in mind:
Jenn's basic argument is that Methodists who pushed for the use of non-alcoholic "wine" in the Eucharist in the late 19th century were doing so based on a coherent theological/philosophical point of view based in "common-sense realism." I'm no expert on commonsense realism, so I won't discuss the more technical historical-philosophical aspect of Jenn's argument. But she captures the American Victorian Protestant ethos brilliantly. The theologians, moral reformers, and authors of household advice manuals whose work she examines all shared the conviction that clear thinking about the world, based on reliable sense impressions and free from undue influence by passion or imagination, was key to personal morality, social welfare, and true religion. They were deeply suspicious of the irrationality and self-indulgence that they identified with Romantic poets on the one hand and with Catholic immigrants on the other. They believed sincerely that "cleanliness is next to godliness" (maybe even identical with it).
The most appropriate symbol for this view of the world was water. Jenn quotes a number of "temperance hymns" which extol the benefits of "pure, cold water" (see p. 62, for instance). Jenn is writing about Methodists, not Mormons, but it may be significant that Mormons (like some early Gnostics) substituted water for the "fruit of the vine" in their version of the Eucharist. Methodists and other mainstream Protestants were too attached to traditional Christianity to follow the Mormon example in this. Indeed, temperance reformers initially did not condemn all alcohol, instead arguing for stricter standards of purity in the production of alcohol and fighting against the distilling trade. Properly produced beer and wine could be consumed healthfully in small quantities (this was John Wesley's view). Hard liquor and the "adulterated" beer and wine often drunk by the lower classes were entirely evil. Benjamin Rush's "temperance thermometer" reflects this early view (p. 21). By the middle of the 19th century, however, temperance advocates had moved on to the condemnation of all alcohol. This brought them into apparent conflict with the Bible, which frequently speaks favorably of wine and seems to mandate its use in the Eucharist. Lacking the claims to additional revelation put forward by the Mormons, how were Methodists and other mainstream American Protestants to handle this apparent conflict? The answer lay in the "two-wine theory," which argued that "pure" wine was in fact non-alcoholic. One of Jenn's most interesting sources (about which I heard a great deal while she was writing the dissertation that eventually became this book) is Frederic R. Lees' Temperance Bible Commentary, which goes through every verse in the Bible discussing wine and argues systematically for the two-wine theory.
The central chapters of the book deal respectively with "Alcohol and Science," "Alcohol and the Overthrow of Reason," "Alcohol, the Ideal Worker, and the Poisoned Chalice," and "Alcohol and the Truth of the Gospel." A further chapter discusses how similar concerns about cleanliness and rationality underlay the move away from the common cup toward small individual cups.
The concluding chapter, beginning "This is the story of how grape juice became holy" (p. 121), is a brilliant summary of the argument of the book as a whole, focusing on the contrast between a contemporary "liturgical" sensibility valuing mystery, ecstasy, and passion and the theological views that motivated the temperance reformers. Jenn is formed by the liturgical tradition within Methodism, and this book is an impressive exercise in getting inside the heads of people with whose assumptions she fundamentally disagrees.
Obviously the book is useful for all grape-juice-using American Protestants (not just Methodists) who want to understand their heritage on this point, as well as for non-American Protestants, American non-Protestants, and even those who are neither American nor Protestant, who may wish to understand the weird practices of this particular tribal family. However, in a society increasingly divided along "culture-war" lines, where people on both sides routinely refuse to see any intellectual validity in the other, the seriousness with which Jenn takes her subjects' ideas may be the greatest significance of the book. (Jenn is not, I'm happy to say, unique in this respect--there are a number of young scholars of American religion who are doing this kind of thing.) It is common to hear liberal intellectuals claim (or more tragically, just assume) that the "great unwashed" of conservative American Protestantism do what they do for fundamentally non-theological reasons, usually because they are being manipulated by millionaires. In the present instance, it is often asserted that the Welch family promoted non-alcoholic Eucharistic "wine" for purely financial considerations. Jenn shows the abundant intellectual roots of Eucharistic grape juice (if juice can have roots), demonstrating that 19th-century American Protestants, right or wrong, had coherent reasons for their views. She also points out that temperance advocates saw themselves as "progressive," interpreting Scripture in the light of science and clearing away the fetid foliage of tradition to make way for the light of common sense and responsible democratic citizenship.
In summary, this book is an engagingly written, often wryly funny work of scholarship that sheds light on some of the basic underlying assumptions of the mainstream 19th-century American Protestant tradition, which continues to shape American society today. For those of us who come from that tradition, the book helps us understand ourselves better. Thanks to Jenn's work, I have a much better understanding of just what it is about my religious heritage that I reject, and why that rejection has brought me where I am today. I stand firmly on the side of mystery and paradox against common sense. And yet when I read this book, I hear the rippling of cool, clear water and I have a better understanding of the moral and spiritual vision that shaped my childhood than I did when I was under its un-enchanting spell.
(Final note: one of the big questions left to be addressed by this book is the role of emotion and even Romanticism in the Wesleyan tradition. Our mutual friend Chris Armstrong of "Grateful to the Dead" tends to emphasize this--he and Jenn have some disagreements on the subject. In my own case, I find that the "Romantic" elements of my heritage are the ones with which I am still most in agreement, while the "common-sense" elements are the ones I am most inclined to reject outright. But this is not a subject that can be addressed adequately within the limits of this review.)