bay leaf
spice or herb / spice-bay-leaf
ローリエ
Bay leaf is the dried leaves of the bay laurel tree, used as a spice (bay leaf, laurel). Sources describe it as slightly bitter, but no source in which people measured the bitterness of the leaf itself has been found.
On this page (7 sections)
Reading the bitterness
A table in a Japanese review describes the taste of laurel (bay leaf) as a well-harmonized aroma of wood, flower, eucalyptus and clove notes with slight bitterness. An explanation by S&B Foods describes differences by origin: European bay leaf from the Mediterranean coast has a faint bitterness, and American bay leaves have somewhat more pronounced bitterness. This describes bitterness strength as differing by origin, but both are descriptions, not numerical measurements of strength.
Several sources write about the difference between fresh and dried leaves. A book chapter states that fresh bay leaves have a bitter, pungent taste, so they are dried before use, being left for 48 to 72 hours after picking. A paper on cultivation in Korea states that bitterness disappears when picked leaves are dried for 1 to 2 days, though saying it disappears may be too strong. A recipe article writes that fresh leaves have a clean bitterness and that drying makes the aroma far stronger. Some sentences in the papers' introductions derive from the same original source, so the independent support is not as large as the number of sources.
For stewed dishes, an explanation by S&B Foods states that leaving the leaf in can bring out bitterness, so it should be removed when the dish is done, and when simmering for a long time it should be taken out after about 1 hour. A recipe article also has a passage asking for the leaf to be taken out partway when simmered long, but its word is harshness, which is a different term from bitterness. Both are explanations of cooking rules of thumb, not experiments measuring which component turns into bitterness after how many minutes.
This body of sources has no result that measured the bitterness of bay leaf numerically. In a test adding a concentrated mixed extract of myrtle, bay leaf and fennel (25:25:50) to almond drink, a 10-member panel's bitterness score rose as the amount of extract increased (regression coefficient +0.17, p = 0.004) and fell when xylitol was added (regression coefficient -0.18, p = 0.020). However, this is a result for a mixed extract, and the contribution to bitterness cannot be separated out for bay leaf, so it cannot be read as the bitterness of bay leaf alone.
Sources for this overview
Checked for this overview: The description of slight bitterness in the review table was used in paragraph 1.
「ローレル」「月桂樹」「ベイリーブス」のお話｜お客様相談センターたより（エスビー食品）
Checked for this overview: The explanation of differences in bitterness by origin was used in paragraph 1.
Checked for this overview: The book's statement that fresh leaves are bitter and are dried for use was used in paragraph 2.
Efficacy of Laurus nobilis L. for Tight Junction Protein Imbalance in Leaky Gut Syndrome
Checked for this overview: The statement that bitterness disappears on drying, and the point that this is too strong, was used in paragraph 2.
料理に使いたいローリエ！役割や代用品は？（デリッシュキッチン）
Checked for this overview: The statement about the bitterness of fresh leaves and the stronger aroma on drying was used in paragraph 2. / The statement using a different word, that harshness is perceived when simmered long, was used in paragraph 3.
Checked for this overview: The point that the introduction's sentence that fresh leaves are bitter derives from the same original source was used in paragraph 2.
ローレル／Laurel｜スパイス&ハーブ検索（エスビー食品 スパイス&ハーブ総合研究所）
Checked for this overview: The explanation that leaving the leaf in can bring out bitterness and that it should be removed after about 1 hour was used in paragraph 3.
Checked for this overview: The result that bitterness rose in a mixed extract, and the point that it is not bay leaf alone, was used in paragraph 4.
Other names: ローレル (ja, identification medium), ベイリーフ (ja, identification unverified)
Follow the connections
bay leaf →— sensory attribute→ bitterness →can be measured separately …→ astringency
Structured claims — open a section to read each claim's confidence, evidence and limits
How processing and cooking change it (2)
Scope: Almond drink. Mixed extract of myrtle, bay leaf and fennel (not bay leaf alone). Panel of 10. 1 to 10 point scale.
Note: The extract is a mixed concentrate of 25% dried myrtle leaf, 25% bay leaf and 50% fennel seed extracted in 30% ethanol, and the contribution to bitterness cannot be separated out for bay leaf. The authors state that the myrtle and bay leaf extracts were high in phenol content. The sensory properties of bay leaf alone cannot be known from this source. The discussion in the text writes '0.35 points per 1% of extract and 0.26 points per 1% of xylitol', which conflicts with the coefficients in Table 3 (+0.17 and -0.18) (recalculating from the 20 formulations in Tables 1 and 2 matches Table 3), so the Table 3 values were adopted. It is not counted as a claim about the bitterness of bay leaf alone.
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spice-bay-leaf —has_perceived_bitterness_affected_by→ (the claim sentence above)Scope: Cooking explanations from a Japanese food company and a recipe medium (for using whole leaves in stews).
Note: This is an explanation of a cooking rule of thumb, not a measurement of which component turns into bitterness after how many minutes. The guideline of 1 hour is the value in the company's explanation. It has not been confirmed by experiment.
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spice-bay-leaf —develops_bitterness_depending_on→ (the claim sentence above)Culture (3)
Scope: A candidate at the level of general knowledge. Regional and naming differences have not been confirmed.
No source connected — this claim has not been verified yet. It is a general-knowledge placeholder, not a confirmed statement.
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spice-bay-leaf —is_used_as→ (the claim sentence above)Scope: Descriptions of the taste of laurel (bay leaf) given in a Japanese review and in an explanation by S&B Foods (slight bitterness; faint bitterness).
Note: These are descriptions, not measurements of intensity. S&B Foods states that it differs by origin (Mediterranean and European: faint bitterness; American bay leaves: somewhat more pronounced bitterness). The taste descriptions in the review's table come from books. The review's table states that laurel contains cineole, but that concerns cooling, not bitterness.
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spice-bay-leaf —has_sensory_attribute→ sensation-bitterScope: Statements about the bitterness of the fresh and whole leaf of bay leaf, and about drying it for use (the introductions of papers and an article for general readers).
Note: The 3 papers are each 1 sentence in the introduction or discussion of a paper on a different subject, and the source of each citation is shown only by a number in the text (we have not confirmed the originals). The phrase 'bitterness disappears on drying' may be too strong, and the cooking sources write 'fresh leaves have bitterness, and drying makes the aroma stronger'. Independence: the sentences 'fresh leaves are bitter' in Benli 2024, Ceylan 2024 (introduction) and Batool 2020 come from the same original (a chapter by Batool 2020). Bagchi and Srivastava in the discussion of Ceylan 2024, the source cited by Shin 2024 (a review by Paparella 2022), and the cooking explanations (S&B Foods and Delish Kitchen) are separate originals. The 4 papers are not 4 originals.
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spice-bay-leaf —has_sensory_attribute→ sensation-bitter