Select node based on sibling properties - HtmlAgilityPack - C#

I have an HTML-document that is structured as follows

<ul class="beverageFacts">
<li>
    <span>Vintage</span> 
    <strong>2007&nbsp;</strong>
</li>
<li>
    <span>ABV</span> 
    <strong>13,0&nbsp;%</strong>
</li>
<li>
    <span>Sugar</span> 
    <strong>5&nbsp;gram/liter</strong>
</li>

I need to parse the values of the <strong>-tags to corresponding string's, depending on what value the <span>-tag has.

I have the following:

String vintage;
String sugar;
String abv;

As of now, I am looping through each child node of the beverageFacts-node checking the values to parse it to the correct corresponding string. The code I have so far to get the "Vintage"-value is the following, though the result is always null.

HtmlNodeCollection childNodes = bevFactNode.ChildNodes;
foreach (HtmlNode subNode in childNodes)
{
    if (subNode.InnerText.TrimStart() == "Vintage")
        vintage = subNode.NextSibling.InnerText.Trim();
}

I believe my selection of the nodes is incorrect, but I cannot figure out how to properly do it in the most efficient way.

Is there an easy way to achieve this?

Edit 2013-07-29

I have tried to remove the whitespaces as suggested by enricoariel in the comments using the following code

        HtmlAgilityPack.HtmlDocument page = new HtmlWeb().Load("http://www.systembolaget.se/" + articleID);

        string cleanDoc = Regex.Replace(page.DocumentNode.OuterHtml, @"\s*(?<capture><(?<markUp>\w+)>.*<\/\k<markUp>>)\s*", "${capture}", RegexOptions.Singleline);

        HtmlDocument cleanPage = new HtmlDocument();
        cleanPage.LoadHtml(cleanDoc);

The resulting is still

 String vintage = null;