Change height of an expansion tile in flutter

Add this block

listTileTheme: ListTileTheme.of(context).copyWith(
//               dense: true,
              minVerticalPadding: isExpanded ? null : 20,
            ),

in the wrapping Theme class

Adding that allows you to control the theme of ListTile which is basically what Expansion ListTile is made of.

So you would have

  Widget additiveCard(
  BuildContext context, List<FoodAdditive> additives, Product product, bool good) {
  String subtitleText = good ? "השפעה נמוכה" : "השפעה גבוהה";

  return Theme(
    data: Theme.of(context).copyWith(
      dividerColor: Colors.transparent,
      listTileTheme: ListTileTheme.of(context).copyWith(
//               dense: true,
              minVerticalPadding: isExpanded ? null : 20,
       ),
    ),
    child: ExpansionTile(
      tilePadding: EdgeInsets.symmetric(horizontal: 16),
      onExpansionChanged: (bool expanding) {
        setState(() => isExpanded = expanding);
        isExpanded ? _controller.forward() : _controller.reverse();
      },
      title: Row(
        children: [
          Expanded(
            child: ListTile(
              contentPadding: EdgeInsets.zero,
              title: Text(
                getTitle("תוספים"),
                style: TextStyle(
                  fontWeight: FontWeight.bold,
                ),
              ),
              leading: Icon(Icons.science),
              subtitle: Text(subtitleText),
            ),
          ),
          Row(
            mainAxisSize: MainAxisSize.min,
            children: [
              buildRatingCircle(16, good ? Colors.green : Colors.red),

            ],
          ),
        ],
      ),
      children: [
        Padding(
            padding: const EdgeInsets.all(8.0),
            child: Align(
              alignment: Alignment.centerRight,
              child: Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.end,
                  children: product
                      .countAdditivesByRating(additives)
                      .entries
                      .where((entry) => entry.value > 0)
                      .map((entry) {
                    int rating = entry.key;
                    int ratingCount = entry.value;
                    return buildAdditiveCircle(16, ratingCount, rating);
                  })
                      .toList()
                      .reversed
                      .toList(),
                ),
              ),
            ),
          ),
      ],
    ),
  );
}

It gives a flicker behaviour when switching between collapsed and expanded view, but I think you can modify the minVerticalPadding’s value to get the best possible outcome.