• <strong id="pddju"></strong>
  • <span id="pddju"><blockquote id="pddju"></blockquote></span>

      <acronym id="pddju"></acronym>

        <optgroup id="pddju"></optgroup><optgroup id="pddju"><em id="pddju"><del id="pddju"></del></em></optgroup>

        手機APP下載

        您現在的位置: 首頁 > 在線廣播 > 科學美國人 > 科學美國人科學系列 > 正文

        科學美國人60秒:啤酒花可能使啤酒爆炸

        來源:可可英語 編輯:aimee ?  VIP免費外教試聽課 |  可可官方微信:ikekenet
         下載MP3到電腦  批量下載MP3和LRC到手機
        加載中..
        eh7HL,KPVf!&

        HrARHQ_q(jUw

        This is Scientific American — 60-Second Science. I'm Christopher Intagliata.
        The Allagash Brewing Company, in Maine, makes a lot of "bottle-conditioned" beers — brews that get their carbonation by fermenting a second time, in the bottle, as yeast belch out CO2.
        "And because they do bottle conditioning they're meticulous about monitoring package pressures. It's a way for them to follow the progression of this re-fermentation in the bottle." Thomas Shellhammer is a brewing scientist at Oregon State University. Who freely acknowledges: "It's a fun job. Science and beer."
        Anyway, not long ago, Allagash noticed some very high pressures in some of their bottles. Not quite exploding. But alarming enough for them to give Shellhammer a call.
        What he and his colleague Kaylyn Kirkpatrick found was that hops — the bittering agent in beers — might be to blame. Because the aromatic flowers contain enzymes that can chew up starch. Typically, when hop flowers are added during the initial cooking of the fermentable brew, those key enzymes are denatured. And thus the flowers' only role is as a flavoring agent.
        But as the demand for hoppy beers has grown, brewers have been looking for other tricks to get those juicy, fruity, herbal aromas into beers. So they've been what's called "dry-hopping" beers — dumping loads of hops into the beer during or after fermentation, rather than during the initial boil.
        "So there's sort of an upward limit to how much hops you'd want to put in the kettle because the beers just get unpalatably bitter. But if a brewer focuses on dry hopping they can put very large amounts of hops into beer to create intense hoppy flavors."

        4le*U!ZV2NM~

        啤酒.jpg
        Problem is, adding hops late doesn't deactivate their starch-attacking enzymes. And they're able to break down starches the yeasts weren't able to attack, unleashing even more sugar into the brew. And if yeast are still hanging out, as in Allagash's bottle-conditioned beers, that kickstarts additional fermentation. And that boosts alcohol by volume and carbon dioxide concentration — to potentially explosive levels.
        "Basically the hops are taking something that's considered by brewers to be unfermentable, and breaking them down to the point where they can actually re-ferment, or become fermentable, or potentially contribute to sweetness, as beer ages."
        The full detective story is in the Journal of Agricultural and Food Chemistry.
        And, in case you're wondering, Shellhammer's palate does align with his academic interests: "I'm kind of intrigued by the hazy, juicy IPA thing that's going on right now. I'm also a fan of sort of traditional old school IPAs." He's the rare professor whose students use IPAs to raise their GPAs.
        And, in case you're wondering, Shellhammer's palate does align with his academic interests: "I'm kind of intrigued by the hazy, juicy IPA thing that's going on right now. I'm also a fan of sort of traditional old school IPAs." He's the rare professor whose students use IPAs to raise their GPAs.
        Thanks for listening for Scientific American — 60-Second Science Science. I'm Christopher Intagliata.

        c9QUAlV,gbIc

        V[#VIz-7&6b

        .@7(e^&rzlu&~yx&d#73yja]qmd*GAtGZzvvQsK81f6[oB

        重點單詞   查看全部解釋    
        intrigued

        想一想再看

        adj. 好奇的;被迷住了的 v. 引起…的興趣;使迷惑

         
        traditional [trə'diʃənəl]

        想一想再看

        adj. 傳統的

         
        chew [tʃu:]

        想一想再看

        vt. 咀嚼,嚼碎,損壞
        vi. 咀嚼

         
        concentration [.kɔnsen'treiʃən]

        想一想再看

        n. 集中,專心,濃度

         
        deactivate [di:'æktiveit]

        想一想再看

        vt. 使無效;使不活動;遣散;復員

        聯想記憶
        belch [beltʃ]

        想一想再看

        v. 打嗝,噴出

        聯想記憶
        initial [i'niʃəl]

        想一想再看

        n. (詞)首字母
        adj. 開始的,最初的,

        聯想記憶
        aromatic [.ærəu'mætik]

        想一想再看

        adj. 芳香的 n. 芳香植物,芳香族化合物

        聯想記憶
        intense [in'tens]

        想一想再看

        adj. 強烈的,劇烈的,熱烈的

        聯想記憶
        academic [.ækə'demik]

        想一想再看

        adj. 學術的,學院的,理論的
        n.

         
        ?
        發布評論我來說2句

          英語學習推薦

          • 英語聽寫訓練
            聽寫強化訓練系統有聽寫比對,按句停頓,中文翻譯、聽寫錯詞提示等特色功能.
          • 可可英語微信:ikekenet
            關注可可英語官方微信,每天將會向大家推送短小精悍的英語學習資料..

          科學美國人60秒

          可可英語官方微信(微信號:ikekenet)

          每天向大家推送短小精悍的英語學習資料.

          添加方式1.掃描上方可可官方微信二維碼。
          添加方式2.搜索微信號ikekenet添加即可。
          在线电影