Piedmont.

THE KINGDOM OF NEBBIOLO

From the Tortonian marls of Barolo to the sandy slopes of Roero, discover Piedmont's natural wine renaissance—where traditionalists meet radicals, and Nebbiolo returns to concrete and wild yeast

Piedmont Natural Wine Guide: The Kingdom of Nebbiolo | Unfiltered Barolos & Living Moscato
58k Hectares Under Vine
59 DOCs & DOCGs
1840s Barolo Born
1993 Valli Unite Founded

Beyond Barolo & Barriques

When tradition meets radical naturalism

Piedmont—"foot of the mountains"—sits in Italy's northwest, cradled by the Alps to the north and the Apennines to the south. It is Italy's most Burgundian region: fiercely terroir-focused, dominated by small growers, historically bound to native grapes (Nebbiolo, Barbera, Dolcetto), and obsessed with food and wine pairing. For centuries, Barolo and Barbaresco were Italy's "wines of kings," traditionalists battling modernists over French barriques versus large Slavonian casks.

This guide explores the third way of Piedmontese wine—the natural wine movement that rejects both the heavy extraction of 1980s modernism and the rigid orthodoxy of traditionalism. Stefano Bellotti (Cascina degli Ulivi, Gavi) pioneered biodynamic farming and amphora aging of Timorasso before his passing in 2018, inspiring a generation. Valli Unite (Alessandria) formed as a cooperative in 1991, proving that Barbera and Dolcetto could be made without sulfur by communal labor. Alex della Vecchia (Casa Belfi) revolutionized Moscato d'Asti by making it dry, pet-nat, and wild-fermented. Nadia Verrua (Cascina Tavijn) transforms Grignolino and Ruché into glou-glou naturals from her Monferrato garage.

What distinguishes Piedmont natural wine is terroir extremism—the belief that Tortonian marl (Helvetian) versus Serravallian sandstone matters profoundly, even when making zero-sulfur wine. It is a region where the "garagiste" (garage winemaker) culture thrives alongside ancient noble estates, where a producer might vinify Nebbiolo in concrete eggs or Georgian qvevri while their neighbor maintains 19th-century tradition. The result is wine with structure: natural Barolo that ages 20 years, living Moscato that ferments in bottle, and field blends that taste of the fog (nebbia) from which Nebbiolo takes its name.

Key Facts

  • Location: Northwest Italy, Alpine foothills
  • History: Celtic, Roman, then Savoyard
  • Key Regions: Langhe, Roero, Monferrato, Gavi, Tortona
  • Main Grapes: Nebbiolo, Barbera, Dolcetto, Moscato, Arneis
  • Method: Biodynamic, concrete, old wood, wild yeast
  • Style: Structured, acidic, tannic, terroir-driven
  • Notable: Highest concentration of biodynamic producers in Italy

From Roman Vines to Valli Unite

Two millennia of alpine foothill viticulture

125 BC

Roman Foundations

Roman consul Marcus Aemilius Scaurus establishes Alba Pompeia (modern Alba). Titus Livius mentions "Alban wines" as prized throughout the empire. The Taurini (Celtic tribe) already cultivated vines before Roman arrival. The Ligurians and Celts contributed to the genetic diversity of local grapes. The "Vitis vinifera" arrived via Greek colonies in Liguria, then moved inland to the Po Valley.

Middle Ages

Monasteries & Marchesi

Benedictine and Cistercian monks (Staffarda, Casanova) preserve viticulture through the Dark Ages. The Marchesi di Barolo, Marchesi di Saluzzo, and Counts of Cavour establish feudal vineyard systems. Nebbiolo emerges as the noble variety, distinguished from "common" Barbera and Dolcetto. The "Nebbia" (fog) reference appears in 13th century documents. The House of Savoy promotes Piedmontese wine in Turin and across Europe.

1840s

The Birth of Barolo

Camillo Benso, Count of Cavour (statesman), and Giulia Colbert Falletti, Marchesa di Barolo, employ French oenologist Louis Oudart to create "Barolo" as a dry, structured wine (previously sweet and fizzy). The "King of Wines, Wine of Kings" is born. Barbaresco follows. The "traditional" method—long maceration (20-30 days), large Slavonian oak "botti"—is established. Phylloxera hits later than France (1880s), devastating the region.

1980s

The Modernist Wars

Elio Altare and Angelo Gaja introduce French barriques (small oak), rotary fermenters, and "green harvesting" to Barolo. The "Barolo Wars" divide the region: traditionalists (Bartolo Mascarello, Giuseppe Rinaldi) defend long maceration and large casks; modernists favor new oak and short extraction. The debate shapes global perception of Italian wine. "Natural wine" barely exists as a concept, though some traditionalists use native yeast and minimal sulfur.

1991

Valli Unite & The Cooperative Revolution

Three friends (Carpente, Degiacomi, Ferracuti) establish "Valli Unite" in the Alessandria hills (Monferrato), combining their vineyards into a communal, organic farm. They reject industrial agriculture and wine chemicals entirely. This coincides with the arrival of "biodynamics" (Steiner's theories) in Barolo (Bartolo Mascarello experiments). The "natural wine" seed is planted in the Langhe, though met with skepticism by the establishment.

2000s-Present

The Third Wave

Stefano Bellotti (Cascina degli Ulivi) becomes the philosophical father of Piedmont natural wine, aging Timorasso in amphorae and refusing certifications. Nadia Verrua (Cascina Tavijn) and others champion "vinification integrale" (whole cluster, wild ferment). Casa Belfi (Alex della Vecchia) revolutionizes Moscato. The "Barolo Boys" generation gives way to their children— Elena Rinaldi, Maria Teresa Mascarello—who often embrace lower sulfur and organic farming, bridging traditional and natural. Today, over 200 producers identify as "natural" or "low-intervention" in a region of 18,000 growers.

"Barolo is not made in the cellar with chemistry. It is made in the vineyard with patience, and in the bottle with time. The barrique is a crutch for weak grapes." — Bartolo Mascarello, Traditionalist Icon (1927-2005)

Langhe, Roero & Monferrato

Tortonian marls, sandstones, and the Tanaro River

🍷 The Langhe

South of Alba, the heartland of Nebbiolo. Divided into Barolo (11 villages including La Morra, Serralunga, Monforte) and Barbaresco (3 villages: Barbaresco, Neive, Treiso). Two soil types dominate: Tortonian (blue/grey marl, younger, produces elegant, aromatic wines—La Morra) and Helvetian/Serravallian (white/ grey, older, sandstone-heavy, produces structured, tannic wines—Serralunga). Altitude 200-500m. Natural winemakers here (Le Strette, Brezza) emphasize vineyard expression over cellar manipulation. The "Tajarin" pasta zone.

🌸 Roero

North of Alba, across the Tanaro River. Sandy soils (from ancient seabeds) dominate, creating lighter, more aromatic expressions of Nebbiolo (Roero DOCG requires 95% Nebbiolo, 95% minimum). Also home to Arneis (white grape, "little rascal"), which natural winemakers skin-ferment into orange wines. Less prestigious than Langhe historically, but natural producers (Malvira, etc.) champion its transparency. Steep, sandblasted hills prone to erosion.

🍇 Monferrato

East and south of Asti, rolling hills of calcareous clay and sandstone. The kingdom of Barbera (Barbera d'Asti DOCG) and Moscato (d'Asti). Also Dolcetto, Grignolino, and Freisa. More democratic wine culture than the aristocratic Langhe. Valli Unite operates here (Alessandria hills). The "infernot"—underground cellars carved in tufa rock—characterize the landscape. Natural wine thrives here due to lower land costs and experimental spirit.

🌿 Gavi

Southeast Piedmont (Alessandria province), bordering Liguria. Cortese grape (white) is king, producing Gavi DOCG. Historically neutral and acidic, natural winemakers (Stefano Bellotti legacy) treat it with skin contact and amphora aging, creating structured, age-worthy whites. Clay-limestone soils with iron-rich red sands (ferretto). Colli Tortonesi nearby is home to Timorasso—the "white Barolo."

⛰️ Colli Tortonesi

Far eastern Piedmont, on the border with Emilia-Romagna and Liguria. Volcanic and calcareous soils. Home to Timorasso (Derthona), an ancient white grape nearly extinct, revived by Walter Massa and championed by natural producers. Also Ortrugo and Malvasia. Mountainous, wilder, less touristy than Langhe. The "wild west" of Piedmont natural wine.

🌊 Alto Piemonte

North, near Lake Maggiore and the Alps (Ghemme, Gattinara, Lessona). Alpine foothills, porphyry and volcanic soils. Nebbiolo (called Spanna locally) produces lighter, more ethereal, mineral wines than Barolo. Historic region (once more famous than Barolo) devastated by phylloxera and industrialization. Natural producers (Antoniotti, Sperino, Roses) reviving old vines and traditional "piemontese" methods with minimal sulfur.

Regional Natural Wine Character

Region Soil Key Grapes Natural Wine Character
Barolo Tortonian/Helvetian marl Nebbiolo Structured, tannic, age-worthy
Barbaresco Tortonian limestone Nebbiolo Elegant, floral, refined
Roero Sand, limestone Nebbiolo, Arneis Aromatic, lighter, sandy texture
Monferrato Calcareous clay Barbera, Moscato Juicy, acidic, glou-glou
Gavi/Tortona Clay, limestone, ferretto Cortese, Timorasso Mineral, textured whites

The Featured Producers

From Barolo traditionalists to Monferrato radicals

Langhe – Nebbiolo Unfiltered

Giorgio Viora & Brothers
Le Strette, Novello (Barolo)
Young brothers (Gianluca, Andrea, Giorgio) farming 5 hectares in Novello (Tortonian soils) since 1997. Organic certified, extremely low sulfur (10-20mg/l max), native yeast. "Barolo Novello" is the flagship—traditional long maceration (40+ days) but aged in old barrels and bottled without filtration. Also "Dolcetto" and "Langhe Nebbiolo" that drink like village Burgundy. Part of the "new traditional" movement—honoring the old ways (Botticella aging) but with organic viticulture and minimal cellar work. Tiny production (800 cases).
New Traditional Novello Low Sulfur Barolo
Marina Marcarino
Punset, Barbaresco
Organic since 1982 (rare for the era), certified organic, low sulfur. "Basarin" Barbaresco is the star—whole berry fermentation, old Slavonian casks, bottled unfiltered. Also makes "Langhe Nebbiolo" and "Dolcetto" with carbonic elements. Marina is a pioneer of organic viticulture in a region that resisted it, facing ridicule from neighbors who now follow her lead. The wines are pure, transparent, floral—true expressions of Barbaresco's limestone terroir.
Organic Pioneer Barbaresco Basarin Unfiltered
Enrico Brezza & Family
Brezza, Barolo
Historic family estate (founded 1910) in the heart of Barolo village, farming organically since 2010. "Cannubi," "Sarmassa," and "Castellero" crus. Traditional long maceration (30-40 days), large oak botti, minimal sulfur at bottling only. Not "natural" by anarchist standards, but "natural-leaning" traditionalist. The wines show that Barolo's terroir shines when technology is minimized. Also excellent "Barbera d'Alba" and "Dolcetto." The transition to organic caused a drop in quantity but increase in quality.
Traditionalist Organic Barolo Crus Heritage

Monferrato & Alessandria – The Radical Hills

Valli Unite
Vho (Alessandria), Monferrato
Cooperative of three families (Carpente, Degiacomi, Ferracuti) farming 35 hectares since 1991. Organic/biodynamic, zero sulfur in many cuvées, communal living and working. "Otium" (Barbera/Dolcetto blend) and "Albarusso" (Barbera) are the natural wine staples—juicy, funky, alive. Also make "Moscato Secco" (dry Moscato) which was revolutionary. The winery operates as a community—shared profits, shared labor, shared meals. Represents the anarcho-syndicalist soul of Italian natural wine. Wines are rustic, honest, variable, but always authentic.
Cooperative Zero Sulfur Communal Monferrato
Nadia Verrua
Cascina Tavijn, Asti (Monferrato)
The queen of Monferrato natural wine. Works 7 hectares in the hills around Asti, focusing on indigenous grapes: Grignolino (light, peppery, tannic), Ruché (aromatic, spicy), Barbera, and Malvasia. "Grignolino Ottavio" is legendary—whole cluster, carbonic, zero sulfur, bottled with crown caps. Also "Ruché" and "Barbera Superiore." The winery is literally her garage. Low extraction, high drinkability, "vin de soif" philosophy. Part of the "Astigiani" group of young natural winemakers. Labels feature her dog.
Garagiste Grignolino Ruché Vin de Soif
Franco Rocca
Barbera d'Asti DOCG, Monferrato
Focuses exclusively on Barbera from old vines (50+ years). Organic farming, indigenous yeast, minimal sulfur. "Barbera d'Asti Superiore" is the flagship—aged in old barrels, unfiltered, with the acidity and structure to age 10+ years. Also makes "Barbera del Monferrato" fresher style. Franco is a purist—no international grapes, no barriques, no tricks. The wines are deeply colored, with that characteristic Barbera acidity (tangy, red fruit) but with earth and spice from old vines.
Barbera Specialist Old Vines Monferrato Pure

Gavi, Colli Tortonesi & Whites

Stefano Bellotti (Legacy)
Cascina degli Ulivi, Gavi
Stefano (1957-2018) was the philosophical father of Piedmont natural wine. Farmed 22 hectares in Gavi biodynamically since 1984. Famous for Timorasso ("Derthona") aged in amphorae and old oak—complex, age-worthy whites that rival great Burgundy. Also "Cortese" (Gavi) with skin contact. The estate continues under his family and team. "Montemarino" (field blend) and "A Demua" (macerated Cortese) are cult wines. Stefano proved that white Piedmontese wine could be as serious as red Barolo, and that amphora aging was compatible with Italian tradition.
Legend Timorasso Amphora Biodynamic
Alex della Vecchia
Casa Belfi, Veneto/Piemonte Border
Technically in Veneto but spiritually Piedmontese (and mentored by Bellotti). Revolutionized Moscato by making it dry, pet-nat, and wild-fermented—the opposite of the sweet, DOCG Moscato d'Asti. "Moscato Secco" and "Moscato Pet-Nat" are the flags. Also makes "Raboso" and "Verduzzo" naturally. Zero sulfur, ancestral method, cloudy. Alex proved that Moscato—the grape of cheap sweet fizz—could be a serious natural wine. Also makes "Col Fondo" Prosecco style.
Moscato Revolution Pet-Nat Zero Sulfur Col Fondo
Walter Massa
Colli Tortonesi
The man who saved Timorasso from extinction in the 1980s. While not strictly "natural" (uses some sulfur, conventional farming historically), his influence on the region is paramount, and many natural producers learned from him. "Sterpi" and "Costa del Sole" are the top Timorassos—mineral, waxy, honeyed with age. Works with local clay soils (white soils). Natural winemakers in Tortona (like those at Valli Unite) consider him the godfather. His sons now work with lower sulfur and organic methods, bridging the gap.
Timorasso Savior Colli Tortonesi Influence Heritage
"We don't make wine with our heads. We make it with our hands in the dirt and our stomachs at the table. If you can't drink a bottle with bread and salami, it's not wine." — Nadia Verrua, Cascina Tavijn

The Grapes of Piemonte

Nebbiolo, Barbera, and the unsung heroes

Indigenous Red • The King

Nebbiolo

Piedmont's noble grape, named for the "nebbia" (fog) that covers the Langhe in October harvest. High polyphenols (tannin and acid), light color, complex aromatics (tar, roses, cherries). Barolo requires 100% Nebbiolo, aged 38 months (18 in wood). Barbaresco requires 26 months (9 in wood). Natural winemakers often extend maceration (40-60 days) to soften tannins without oak, or use whole cluster to add spice. Also made as "Langhe Nebbiolo" (younger, fresher) and "Nebbiolo d'Alba." The ultimate test of terroir—translates soil differences vividly.

  • Style: Tannic, acidic, aromatic, long-lived
  • Natural Wine Role: Long maceration, whole cluster, old wood
  • Top Producers: Le Strette, Punset, Brezza
  • Regions: Barolo, Barbaresco, Roero, Alto Piemonte
  • Notable: 3 distinct sub-varieties (Lampia, Michet, Rosé)
Indigenous Red • The Workhorse

Barbera

High-yielding, high-acid, low-tannin grape covering more acres than Nebbiolo in Piedmont. Historically "everyday wine" for farmers. "Barbera d'Asti" and "Barbera d'Alba" are the main DOCGs. Natural winemakers (Valli Unite, Franco Rocca) embrace its natural acidity, making juicy, purple, glou-glou wines or serious, aged versions. Unlike Nebbiolo, it ripens earlier and avoids autumn rains. Flavors of sour cherry, blackberry, and spice. Natural versions often show a "funk" or " Brett" that complements the acid—controversial but beloved.

  • Style: High acid, low tannin, fruity, purple
  • Natural Wine Role: Glou-glou, carbonic, everyday drinking
  • Top Producers: Valli Unite, Franco Rocca, Nadia Verrua
  • Regions: Monferrato, Alba, Asti
  • Notable: 3x more planted than Nebbiolo
Indigenous Red • The Light One

Grignolino

"Little grapes" or possibly from "grignole" (pips)—the grape is full of seeds, making it tannic despite light color. Grown in Monferrato and Asti. Makes pale, translucent, peppery, herbaceous wines similar to Poulsard or Pinot Noir. Natural winemakers (Nadia Verrua) champion it as the ultimate "vin de soif"—chillable, low alcohol (11-12%), perfect for summer. Often bottled with crown caps. Historically undervalued, now a natural wine darling. Flavors of white pepper, strawberry, rhubarb, and herbs.

  • Style: Light, peppery, tannic, herbaceous
  • Natural Wine Role: Chillable red, carbonic, crown cap
  • Top Producers: Cascina Tavijn (Nadia Verrua)
  • Regions: Monferrato, Asti
  • Notable: Many pips (seeds) = high tannin, low color

More Piedmont Varieties

From Dolcetto to Timorasso

Dolcetto: "Little sweet one" (actually dry). Early-ripening, dark, fruity, bitter almond finish. Natural versions from Le Strette and others are juicy and immediate.

Ruché: Rare aromatic red from Castagnole Monferrato. Spicy, floral (rose), medium body. Nadia Verrua makes a cult version.

Freisa: Related to Nebbiolo, tannic, often slightly fizzy ("Freisa Frizzante"). Can be challenging; natural versions embrace the wildness.

Pelaverga: From Verduno (Barolo village). Peppery, strawberry notes, light color. Used to add spice to Barolo blends historically.

Timorasso: The "white Barolo" from Tortona. Aromatic, mineral, ages 20+ years. Bellotti and Massa are the masters.

Arneis: "Little rascal" from Roero. Historically difficult, now popular white. Natural versions skin-fermented for texture.

Moscato: Muscat Blanc à Petits Grains. Usually sweet sparkling (Asti), but natural winemakers (Casa Belfi) make it dry and pet-nat.

Cortese: Gavi's grape. Neutral, acidic; natural winemakers use skin contact to add interest.

Food Pairing & Piemontese Cuisine

Tajarin, truffles, and bagna cauda

For Barolo & Barbaresco

The kings need richness

  • Brasato al Barolo: Beef braised in Barolo wine
  • Carne cruda: Raw beef with truffle, olive oil, lemon
  • Agnolotti: Pasta pockets with meat filling, butter, sage
  • Guinea fowl: Roasted with hazelnuts
  • Aged Parmigiano: 36-month cheese

For Barbera & Dolcetto

Acidity meets fat

  • Vitello tonnato: Cold veal with tuna-caper sauce
  • Bagna cauda: Hot anchovy-garlic dip for vegetables
  • Fritto misto: Fried mixed meats and vegetables
  • Polenta: With mushrooms or sausage
  • Pizza: Alba style with local cheese

For Grignolino & Light Reds

Chillable reds meet antipasti

  • Salumi: Salame di cavallo (horse salami), finocchiona
  • Insalata russa: Russian salad with vegetables, mayo
  • Acciughe: Anchovies with butter and bread
  • Tomato salad: With basil and olive oil
  • Fried fish: From Lake Maggiore or Tanaro River

For Whites & Pet-Nats

Timorasso to Moscato

  • Tajarin: Thin egg-yolk pasta with butter and truffle
  • Fonduta: Fontina cheese fondue
  • Crostacei: Langoustines, shrimp (with Timorasso)
  • Zabaione: Dessert with Moscato (traditional)
  • Amaretti: Almond cookies with sweet wines

Piemontese Culinary Traditions

The sacred truffle and the slow food movement

Tartufo Bianco: White truffle from Alba (October-December). Shaved raw over tajarin, eggs, or risotto. Never cook it. Paired with old Barolo or Barbaresco.

Slow Food: Born in Bra (Piedmont) in 1986. The philosophy aligns with natural wine—anti-industrial, pro-terroir, pro-small producer. Visit the University of Gastronomic Sciences in Pollenzo.

Antica Trattoria: Traditional restaurants (Da Cesare, Bovio, etc.) often have the best cellars for traditional Barolo, but natural wine bars (Consorzio, La Fiorida) offer the new wave.

Merenda Sinoira: The "afternoon snack" that becomes dinner—bagna cauda, raw vegetables, boiled meats. Natural Dolcetto or Grignolino are perfect here.

Chocolate: Turin is the chocolate capital. Gianduja (hazelnut chocolate) with Brachetto (sweet red) or Moscato.

Visiting Natural Piemonte

From Alba's towers to Asti's hills

🍷 Langhe & Barolo

Base in Alba (train from Turin). Barolo village: Marchesi di Barolo (historic), Brezza (natural-leaning), Bartolo Mascarello (shrine to traditionalism). La Morra: Le Strette (appointment). Monforte: Serralunga producers. Novello: Le Strette. Eat at Bovio (La Morra, view) or Piazza Duomo (Alba, 3 Michelin stars). Sleep in Barolo or Serralunga (agriturismos). Visit WiMu (Wine Museum in Barolo castle).

🌸 Monferrato & Asti

Base in Asti or Moncalvo. Nadia Verrua (Cascina Tavijn—appointment, garage winery experience). Franco Rocca (Barbera country). Valli Unite (Vho, communal meal possible). Canelli: Underground cathedrals (Unesco, for sparkling wine). Less touristy than Langhe, more "authentic" rural Italy. Visit Infernot (underground cellars in Monferrato). Eat bagna cauda at local trattorias.

🌿 Gavi & Tortona

Base in Tortona or Novi Ligure. Cascina degli Ulivi (Stefano Bellotti's legacy—appointment essential, spiritual experience). Walter Massa (Timorasso master). Valli Unite also has presence here. Visit Volpedo (birthplace of painter Pellizza da Volpedo). Colli Tortonesi are wilder, less polished than Langhe. Great for hiking between vineyards. Eat tortello di Tortona (herb-filled pasta).

7-Day Natural Wine Itinerary

Day 1 - Turin: Arrive Torino (Turin). Eataly (birthplace) for dinner. Overnight Turin.

Day 2 - Barolo: Drive/train to Barolo. WiMu museum. Marchesi di Barolo (historic). Dinner at Bovio. Overnight Barolo.

Day 3 - La Morra & Serralunga: Le Strette (tasting with Giorgio). Brezza (Barolo). Cavallotto (organic). Overnight Barolo.

Day 4 - Barbaresco: Drive to Barbaresco. Punset (Marina Marcarino). Produttori del Barbaresco (co-op, contrast). Overnight Neive or Alba.

Day 5 - Monferrato: Drive to Asti. Nadia Verrua (garage visit). Franco Rocca. Valli Unite (communal lunch if possible). Overnight Asti.

Day 6 - Colli Tortonesi: Drive to Tortona. Cascina degli Ulivi (Bellotti's estate—emotional visit). Walter Massa. Overnight Tortona.

Day 7 - Return: Return to Turin or Milan (1 hour) for departure.

Timing: Visit October-November for truffle season (expensive, crowded) or May-June for spring (green, quiet). Avoid harvest (September) unless you have appointments.

Piedmont Essentials

  • 58,000 hectares under vine
  • 59 DOCs and DOCGs
  • 18,000+ wine growers
  • Nebbiolo: 5,500 hectares only
  • Birthplace of Slow Food

Featured Producers

  • Le Strette (Barolo)
  • Valli Unite (Monferrato)
  • Cascina degli Ulivi (Gavi)
  • Nadia Verrua (Monferrato)
  • Punset (Barbaresco)

Key Varieties

  • Nebbiolo (Barolo/Barbaresco)
  • Barbera (Monferrato)
  • Dolcetto (Langhe)
  • Grignolino (Asti)
  • Timorasso (Tortona)

Visit Info

  • Best: May-June or Oct-Nov
  • Fly to Turin or Milan
  • Base: Alba or Asti
  • Car recommended
  • Book restaurants ahead
Sources: Consorzio del Barolo, Slow Food, Valli Unite, Cascina degli Ulivi, Wine Spectator, Gambero Rosso