RESIDENTS OF Chinon, France, have made the most of their illustrious native son, François Rabelais, attaching his name to schools, hospitals, streets and even restaurants and bars. The last two seem particularly fitting since the 16th-century writer and doctor was nearly as famous for his appetite as he was for his prose. A fan of local wines, Rabelais could also pen a pretty good tasting note. In one example, he compared the wines of Chinon to taffeta.

While Rabelais has remained famous, the wines he admired haven’t fared quite as well. Chinon and nearby towns such as Saumur, Bourgueil, Vouvray and Montlouis-sur-Loire today produce some of the best-valued wines in the Loire Valley—if not all of France. Diverse reds and whites, they pair well with food, and top examples improve over the years. Yet even the very best wines are often underrated and overlooked. They’re certainly underpriced. A good bottle of Loire can cost less than $20, while a good Bordeaux can easily cost more than 10 times that amount.

As a longtime fan of Loire Valley wines, I’ve never understood why they’ve remained so affordable. (Not that I’m complaining, of course.) I traveled to the region last month to talk with top producers, taste a few favorites and find out a bit more.

The Loire River, stretching 634 miles from the Massif Central in the center of France to the Atlantic Ocean, is the longest in the country. The Loire Valley wine region is accordingly large, with 185,000 or so vineyard acres planted with a variety of grapes. In the midsection, where I spent most of my time, Chenin Blanc and Cabernet Franc dominate. But even those grapes yield diverse offerings. Chenin Blancs here range from dry and mineral to unctuous and intensely sweet. The Cabernet Franc category, meanwhile, encompasses lithe, supple wines as well as rich, full-bodied bottlings.

I started my trip in Chinon, at Domaine Jean-Maurice Raffault, where winemaker Rodolphe Raffault’s family has been cultivating grapes for centuries. The estate’s cellar is a prime example of the best the Loire has to offer: versatile, affordable, notably ageworthy wines.

Mr. Raffault opened a range of bottles for me, including a juicy 2015 Chinon rosé ($15), a 2015 Les Galuches that he said was “very popular in French bistros” and cost a mere $18, and one of his best wines, the 2014 Clos d’Isoré, a rich, complex red that will be on the U.S. market later this year for around $22 a bottle. Near the end of our tasting, he brought out a beautiful, still vibrant 1989 Les Picasses, proving the longevity of a first-rate Chinon.

My next stop was on the other side of town at Domaine Bernard Baudry, run by winemaker Matthieu Baudry and his father, Bernard, who founded the estate in 1975. The Baudrys have made a name for themselves with lively, bright natural wines known for their richness and depth. But Matthieu Baudry said the area’s reputation had been hurt by some winemakers who were “too technical” and used “too much stainless steel and too much herbicide,” resulting in sterile, uninteresting wines.

When we drove to a hilltop overlooking a patchwork of vineyards, the vivid green of the Baudry plot was a marked contrast to the brownish patch that belonged to his neighbor, who, as if on cue, was spraying his land. (A few weeks after my visit, Loire Valley winemakers faced the potentially devastating effects of a multiday frost. I only hope that the damage won’t be too severe.)

Mr. Baudry’s wines, as full of life as his vineyard, demonstrate the range of the Cabernet Franc grape: from a delicious, sprightly 2015 rosé to the 2014 Les Grezeaux, a rich, concentrated wine that’s just arriving on the market and is a remarkable deal at $27 a bottle.

About half an hour’s drive east, in Montlouis-sur-Loire, Jacky Blot produces equally vivid wines at Domaine de la Taille aux Loups. A wine broker turned wine producer, Mr. Blot owns vineyards in both Montlouis and nearby Vouvray. Though he must now label his Vouvray wines with the lowly “Vin de France” name (usually reserved for simple table wines) after a change in appellation laws, his wines are first-rate. My favorites from the 2014 vintage were the beautifully mineral Clos de la Bretonnière ($30) and Clos de Venise, both from Vouvray, and the Remus Plus, his signature bottling from Montlouis-sur-Loire.

Mr. Blot also produces a terrific dry sparkling wine, Triple Zéro ($30), named for the purity of the winemaking process. Unlike most sparkling wines, no liqueur de tirage (sugar syrup) is added to Triple Zéro post-fermentation. Excess sugar is Mr. Blot’s bête noir.

Across the Loire River, in Vouvray, Domaine Huet has long been famous for its dry and sweet wines. Though some feared the 2003 purchase of the estate by New York businessman Anthony Hwang, the estate has flourished in recent years.

When I arrived, director Jean-Bernard Berthomé was leading a tasting of both sweet and dry varieties for members of the Rare Wine Co., the winery’s American importer. Blake Murdock, a managing director of the Brisbane, Calif.-based company, said Domaine Huet’s dry Chenins are particularly sought-after in the U.S. The sweeter wines, he added, sold somewhat more slowly.

So why are the estate’s wines, so universally clamored for, still so reasonably priced? “We want to respect the market and respect the consumer,” said Sarah Hwang, domaine president and daughter of Mr. Hwang. “We want the consumer to enjoy the wines.” It’s also a matter of showing loyalty to their loyal customers, she added. (If only Bordeaux winemakers, who notoriously raise their prices every time a vintage is above average, operated this way.)

François Pinon, the genial proprietor of Domaine Pinon, my last stop, also seeks to balance pleasure and price. Mr. Pinon makes terrific still and sparkling Chenin Blancs at his organic Vouvray estate. His sparkling wines come in two versions: brut nondosé (dry) and brut nonvintage (with a bit of sugar). Both are incredibly affordable, at $25 and $22 a bottle, respectively.

When I mentioned Mr. Blot’s invective against sugary, cheap wines, Mr. Pinon agreed, saying some producers took “the auto route” instead of “the little path.” There was no question as to which road Mr. Pinon had pursued.

I was particularly keen on his brut nonvintage, which wasn’t sweet but simply well-balanced and harmonious. “I add sugar to make it a more social wine,” Mr. Pinon said, with a smile. Indeed, it made me want to stay for a longer chat, but I had a train to catch.

As I drove away, I recalled the words of another native son—one perhaps more famous than Rabelais—Honoré de Balzac. Although Balzac’s name is synonymous with coffee (he was said to drink 50 cups a day), he was also an advocate and consumer of Vouvray. As noted in a 1994 biography by Graham Robb, Balzac once wrote that he could “gorge himself like a camel at an oasis on food and drink—preferably Vouvray—without getting drunk.” At the prices these producers are charging today, wine lovers might be tempted to do the same.

Oenofile // Five Great Bargains From the Loire Valley Photo: F. Martin Ramin/The Wall Street Journal

Domaine François Pinon Vouvray Brut Nonvintage $22

François Pinon crafts this lush sparkling Chenin Blanc at his small domaine in Vouvray. With bright acidity and a touch of sweetness, it’s a pleasurable drink.

Domaine de la Taille aux Loups Montlouis-sur-Loire Triple Zéro $30

This is one of the most distinctive sparkling Chenin Blancs in the Loire. Made by Jacky Blot, with no added sugars, it’s notably minerally and highly polished.

2014 Domaine Huet Le Mont Vouvray Sec $34

This fabled Vouvray estate produces three vineyard-designated wines, each with a specific character and soil. Produced on clay soil, Le Mont Sec is rich and powerful. Unshowy in its youth, this wine develops beautifully over time.

2014 Domaine Bernard Baudry Chinon Les Grezeaux $27

Matthieu and Bernard Baudry’s wines are some of the most highly regarded in Chinon. Their Les Grezeaux is impressively concentrated and deeply flavored.

2015 Domaine Jean-Maurice Raffault Chinon $15

The Raffault family owns vineyards in some of the best sites in Chinon. This fresh, sprightly rosé offers ample evidence of the versatility of Cabernet Franc in this part of the Loire.

Email Lettie at wine@wsj.com