Why Soil Matters: Breaking Down Limestone at Purisima Mountain Vineyard

The Cal­i­forn­ian drought has been on the fore­front of America’s mind. Busi­ness own­ers, par­tic­u­lar­ly those in the agri­cul­ture sec­tor, are think­ing about how the drought will affect their busi­ness. Soil is sec­ond to cli­mate in the impor­tance of vine growth and health, so nat­u­ral­ly soil is a key top­ic in wine coun­try. Here at Beck­men Vine­yards, we are lucky that our vineyard’s soil struc­ture – clay top­soil with a lime­stone sub­soil – per­forms very well in drought con­di­tions. Think about all those times you’ve gone wine tast­ing and your host has men­tioned the loam/​granite/​chalk soil and how it is impor­tant to the fla­vor and mouth­feel of the wine. It may seem unsa­vory to think about dirt when you’re wine tast­ing, but, soil mat­ters. Vines pre­fer well-drain­ing soil types; soils that retain water are ide­al in drought con­di­tions; lime­stone is the per­fect combination.

Superior Water Retention

The Bal­lard Canyon AVA has a small out­crop­ping of lime­stone, which Purisi­ma Moun­tain Vine­yard was built on. The lime­stone is made from fos­silized marine life, cre­at­ed when the San­ta Ynez Val­ley was part of the Pacif­ic Ocean seabed. While vine roots can­not actu­al­ly pen­e­trate through this hard lay­er of rock, there are pre­ex­ist­ing deep crevices in the lime­stone. Roots will search for water and oth­er nutri­ents, chan­nel­ing down into these crevices and cre­at­ing deep root systems.

Cal­ci­um car­bon­ate is the main ele­ment of lime­stone. When the hard lime­stone out­crop­ping dete­ri­o­rates, this cal­ci­um car­bon­ate is then abun­dant in the top­soil, too. In our case, this top­soil is between 12 – 36 inch­es of clay. Soils rich in cal­ci­um are able to retain mois­ture very well in the dry sea­sons, and also have good drainage nec­es­sary for grapevines to thrive. Some of the best wines around the world are made from cal­ci­um-based soils with a high water reten­tion rate: Cham­pagne, Chablis, Loire, Rhône, and cer­tain regions of Aus­tralia, New Zealand, and California.

Absorbing Minerals

Cal­ci­um is a nec­es­sary ele­ment for vine growth and vital­i­ty, both in the soil and in the plant itself. Vine roots can only absorb mol­e­cules, ions, and min­er­als, which are all need­ed to keep the vine alive. Roots grow­ing in cal­ci­um rich soils have an eas­i­er time absorb­ing min­er­als, thus result­ing in a health­i­er plant. When roots are hap­py and healthy, the vine can focus its ener­gy on above ground growth in the canopy and fruit development.

Resistant to Disease Pressures

Cal­ci­um is also locat­ed in the grapes them­selves; cal­ci­um in the grape skin is used as a defense mech­a­nism for fun­gus and dis­ease. If a vine has low amounts of cal­ci­um, how­ev­er, the cal­ci­um is used inside the grape before being used to strength­en the grape skin. A cal­ci­um short­age then weak­ens the grape’s abil­i­ty to pro­tect itself against dis­ease pres­sures. If you have a vine with healthy amounts of cal­ci­um, you are build­ing a strong bar­ri­er against disease.

A Beckmen Example

When Tom and Steve Beck­men found­ed Purisi­ma Moun­tain Vine­yard, they knew the cal­ci­um rich soils would help dis­tin­guish their wines. A prime exam­ple of how the soil helps to cre­ate out­stand­ing wines is our 2013 Purisi­ma Moun­tain Vine­yard Syrah Viog­nier. This wine has a notice­able min­er­al­i­ty, which is eas­i­est to pick-up on the palate. The savory, saline aspect, which entices you to take anoth­er sip as soon as you’ve swal­lowed the wine, is due to the min­er­al­i­ty. Grapes grown on cal­ci­um rich soils also tend to have a high­er acid­i­ty, which cre­ates that long, mouth­wa­ter­ing fin­ish in the 2013 PMV Syrah Viog­nier. If you can’t notice these fla­vors or char­ac­ter­is­tics, don’t wor­ry. Just know that the soil impacts the way wine tastes.

The Beck­mens saw the poten­tial in the soil of the unplant­ed 365 acre ranch they pur­chased in 1996, which they would then turn into one of California’s pre­mier bio­dy­nam­ic vine­yards. The first step in cre­at­ing world class wines is start­ing with the high­est qual­i­ty fruit pos­si­ble. No mat­ter how good your wine­mak­ing skills are, you can’t make good wine from bad grapes; our lime­stone soil ensures that our grapes are one step ahead of the bunch.

If you would like to learn how soil affects the out­come of wine on a deep­er sci­en­tif­ic lev­el, I sug­gest read­ing these two arti­cles on Cal­ci­um in Viti­cul­ture Part 1 and Part 2. I used these arti­cles to help break down the basics of lime­stone soils.