/**
 * @param array $data
 * @param \GeminiLabs\SiteReviews\Modules\Email $email
 * @return array
 */
add_filter('site-reviews/email/compose', function ($data, $email) {
    if (!isset($email->data['review'])) {
        return $data;
    }
    $customFieldNames = [
        'palatability',
        'viscosity',
        'effectiveness',
        'price_quality_ratio',
        'advice',
    ];
    foreach ($customFieldNames as $tag) {
        $data['template-tags'][$tag] = $email->data['review']->custom->get($tag);
    }
    return $data;
}, 10, 2);