Comparing Bay Leaves

By | Monday, August 10, 2015 2 comments
California Bay (left) and True Bay (right)

Living here in the San Francisco Bay area, I find that there is a lot of confusion about the difference between the leaves of our native “California Bay” (which many locals call “Bay Laurel”) and the leaves of true "Bay Laurel”. This isn’t an esoteric distinction, as each of these plants' leaves are used as culinary herbs. I was misinformed about them when I first moved here. Someone told me that the trees growing in the hills were “Bay trees” and that the leaves were great for cooking. Another friend said that they were the same plant from which we get “Bay leaves”, though they were more pungent than the ones grown around the Mediterranean - because of location, not species. Though I understood that gourmets prefer the more refined taste of Mediterranean bay leaves, it only made sense to use the abundantly available leaves of “bay” trees growing right here in the “Bay Area.”

It turns out that “Bay Laurel”, or “True Bay” - the Mediterranean tree from which we get the bay leaves that most people use for cooking - is actually Laurus nobilus. “California Bay” is Umbellularia californica. Both plants are in the same family, Lauraceae, but, as the Latin names show, they are not just different species, they come from different genuses. Being in the same family, it is not surprising that they share a number of physical features and their leaves include similar flavonoids that make them comparable in cooking - but they are not the same.

For the food chemists out there, the Journal of Agriculture and Food Chemistry (J. Agric. Food Chem. 2013, 61, 12283−12291) tells us that 1,8-cineol is the primary essential oil in Laurus nobilusLaurus nobilis contains 57% of this compound, but it makes up only 20% of the essential oil in U. californica. Conversely, Umbellulone is 37% of the essential oil in U. californica, but it isn’t found in L. nobilis at all. Methyleugenol, thymol, and α-terpineol make up 8.4%, 7.8%, and 6.5% of U. californica but are mostly or entirely missing from oil of L. nobilis. There are many other differences in the composition of oil extracted from leaves of these two plants. I have reformatted the table from the JAFC article and provided it for your enjoyment at the bottom of this post.

What’s really important for Californian cooks is the awareness that these are different plants with different flavors. Both leaves are equally edible and both can be used in cooking, but substituting one for the other could produce different results. You can think of it like using Italian basil in place of Thai basil, or, possibly, like replacing lime juice with lemon. If the ingredient is a minor element in a recipe, the results might be indistinguishable. But, if it is a key component of a dish, substitution could create a very different taste.

Though L. nobilus is not native to the area, it grows very well in our Mediterranean climate, so one might run into both of these trees. So, if you're not up to the task of nibbling on a leaf and saying "ahhh, yes, I definitely sense 8.4% methyleugenol", how do you tell them apart? Here are some of the major physical differences between their leaves.

The photo on the left shows the tops of the leaves, the image on the right is of the undersides. In each picture, a leaf of Umbellularia californica is on left and Laurus nobilus is on right

The leaves of Laurus nobilus:
  • Wider than Umbellularia californica
  • Pointier
  • Deeper green
  • Have a slightly wavy edge
  • Thicker and more brittle than those of U. californica
Umbellularia californica leaves:
  • Narrower than those of Laurus nobilus
  • Have rounded tips
  • Are lighter green
  • Have a smooth edge
  • Are thinner, softer, more supple, and more readily bent than those of L. nobilus.
[Note: These differences apply to mature leaves. The young leaves of both trees are light green and soft, making them much harder to distinguish.]

Umbellularia californica in bloom

Umbellularia californica bearing fruit

Umbellularia californica fruit and nut

The following table lists the compounds found in L. nobilus and U. californica. It is from from The Journal of Agriculture and Food Chemistry. It has been edited for format, not content.

Compound  RRI-a  RRI-b  U. cal %  L. nobilius %  ID method
α-pinene 1032 939 0.1 3.8 tR,MS
α-thujene 1035 0.4 tR,MS
β-pinene 1118 979 0.1 3.6 tR,MS
sabinene 1132 975 0.1 5.7 tR,MS
myrcene 1174 991 0.2 tR,MS
α-terpinene 1188 1017 0.2 0.2 tR,MS
dehydro-1,8-cineole 1195 0.9 MS
limonene 1203 1029 0.1 1 tR,MS
1,8-cineole 1213 1031 19.5 57.4 tR,NMR,MS
γ-terpinene 1255 1060 0.3 0.3 tR,MS
p-cymene 1280 1025 2.1 2.2 tR,MS
terpinolene 1290 1089 0.1 0.1 tR,MS
α,p-dimethylstyrene 1452 0.1 MS
trans-sabinene hydrate 1474 1098 0.1 0.6 MS
camphor 1532 0.2 tR,MS
linalool 1553 1097 0.4 0.3 tR,MS
cis-sabinene hydrate 1556 1070 0.1 0.6 MS
trans-p-menth-2-en-1-ol 1571 0.1 0.2 MS
pinocarvone 1586 0.3 tR,MS
bornyl acetate 1591 0.2 tR,MS
terpinen-4-ol 1611 1177 6.6 4 tR,MS
cis-p-menth-2-en-1-ol 1638 0.1 MS
trans-p-mentha-2,8-dien-1-ol 1639 0.5 MS
thuj-3-en-10-al 1642 0.5 MS
myrtenal 1648 0.8 MS
umbellulone 1657 1171 36.7 tR,NMR,MS
trans-pinocarveol 1670 0.5 tR,MS
δ-terpineol 1682 0.6 0.9 MS
α-terpineol 1706 1189 6.5 3.8 tR,MS
α-terpinyl acetate 1709 7 tR,MS
borneol 1719 0.1 tR,MS
β-bisabolene 1741 1506 2.2 MS
phellandral 1744 0.1 0.4 MS
(E)-α-bisabolene 1784 0.5 MS
ar-curcumene 1786 0.1 MS
myrtenol 1804 0.3 tR,MS
nerol 1808 0.1 tR,MS
trans-p-mentha-1(7),8-dien-2-ol 1811 0.3 MS
p-mentha-1,5-dien-7-ol 1814 0.2 MS
2-tridecanone 1815 0.1 MS
trans-carveol 1845 0.1 tR,MS
p-cymen-8-ol 1864 0.2 0.2 tR,MS
cis-p-mentha-1(7),8-diene-2-ol 1896 0.3 MS
cuminyl acetate 1981 0.1 tR,MS
caryophyllene oxide 2008 1583 < 0.1% 0.1 tR,MS
methyleugenol 2030 1404 8.4 0.9 tR,MS
(E)-nerolidol 2050 1563 0.3 tR,MS
p-mentha-1,4-dien-7-ol 2073 0.3 MS
elemol 2096 1550 0.4 MS
cumin alcohol 2113 0.5 0.1 tR,MS
cis-p-menth-3-en-1,2-diol 2184 < 0.1% MS
eugenol 2186 1359 0.4 0.1 tR,MS
γ-eudesmol 2185 0.2 MS
thymol 2198 1290 7.8 tR,MS
carvacrol 2239 1299 < 0.1% tR,MS
elemicine 2245 1557 0.1 MS
α-eudesmol 2250 1654 0.1 MS
β-eudesmol 2257 1651 0.2 0.3 MS
chavicol 2353 0.2 MS
dodecanoic acid 2503 0.3 tR,MS
hexadecanoic acid 2931 0.1 tR,MS

RRI-a: relative retention indices calculated against n-alkanes on polar column.
RRI-b: relative retention indices calculated against n-alkanes on apolar column (Adams, 2001).

U Cal %: % of compound found in Umbellularia californica.
L. Nobilius %, % of compound found in Laurus nobilius
[each of these % calculated from FID data for polar column]

Identification method: tR, identification based on the retention times (tR) of genuine compounds on the HP Innowax column; MS, identified on the basis of computer matching of the mass spectra with those of the Wiley and MassFinder libraries and comparison with literature data.  NMR spectra were recorded on American Varian Mercury plus 400 NMR spectrometers.

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  1. Have you tried a Little Rag Sweet Bay?

    1. Thanks for pointing this plant out. It looks like a nice little tree. The one I am growing is the straight species. This one is Laurus nobilis 'MonRik' PPAF [Note that "PPAF" means "Plant Patent Applied For."] It is said to have been discovered as a sport of Laurus nobilis 'Monem' by Monrovia. Since it is patented, it would only be available from nurseries that retail Monrovia plants. One can only assume that its leaves would be comparable to the straight species in cooking.