【𝐁𝐞𝐞𝐫 𝐌𝐲𝐭𝐡𝐁𝐮𝐬𝐭𝐞𝐫𝐬・𝐖𝐡𝐚𝐭 𝐓𝐡𝐞 𝐇𝐞𝐜𝐤 𝐈𝐬 𝐈𝐁𝐔?】
“I see ‘IBU’ written on many beer menus and labels, but what is IBU and why should I care about it?”
IBU stands for “International Bitterness Units”, it is used to quantify the bitterness level of beer. It is a chemical measurement of the number of bittering compounds, specifically isomerized and oxidized alpha acids, polyphenols, and a few other bittering chemicals, that make your beer taste bitter. Generally speaking, the higher the IBU, the more bitter it will taste.
However, IBU does not measure the perceived bitterness of a beer for the drinker. In other words, just because a beer has a higher IBU doesn't necessarily mean it is perceived as (or tastes) more bitter than a beer with a lower IBU.
IBU vs Perceived Bitterness
How a beer tastes is affected by the balance of ingredients, while hops can contribute to the bitterness of the beer, malt sweetness can balance it out. For instance, a 60 IBU stout may taste less bitter than a 50 IBU hop-forward pale ale. The principle is similar to cooking - you can balance out the bitterness in food by adding more sugar.
1000 IBU?
There’s a limitation on human’s ability to taste bitterness. It is believed that we can only distinguish bitterness from 12 to 80 IBU. Therefore, a normal drinker might not be able to distinguish the difference between a 80 IBU and a 90 IBU beer, even though “in theory” the 90 IBU beer should taste more bitter than the 80 IBU one.
Some breweries claimed they had brewed beers with 1000 IBU. While it might be possible in theory, we might not be able to distinguish the difference between a 1000 IBU and a 100 IBU beer - they might just taste equally bitter! 🥵
The Missing Link
While we know hops usually contribute to the bitterness in beers, there are other ingredients that can also make beers bitter! Some malts (especially black malt), herbs and spices can impart bitterness, but the IBU scale fails to take these bittering agents into account. Dry-hopping can also impart bitterness without producing iso-alpha acids, and IBU would fail to take it into account as well.
IBU: N/A?!
Some breweries might not even disclose the IBU of some beers. Part of the reason is that some beers might not be hop-focused (like sour ale, lambic, etc.), therefore it is not a useful measurement for the drinkers. After all, IBU is a reference, and breweries have their own reasons to disclose the IBU of a beer or not.
Should I care about IBU at all?
If IBU does not 100% reflect the perceived bitterness of the beer, then should I even care? Scientists and professional brewers are working hard to figure out ways to improve the IBU scale for more accurate detection of perceived bitterness. Yet, in the meantime, IBU can still be useful as a reference especially for drinkers who are very sensitive to bitterness.
What can I do to learn more about IBU and bitterness in beers?
It’s always fun to learn more about beers and how you can find beers that suit your taste. Here are some tips for those who are interested in IBU and bitterness in beers:
1. Learn more about beer styles, their ingredients (malts and hops), and their brewing procedure.
2. Taste more beers with different IBU and experience how the brewing process and ingredients contribute to the bitterness level in those beers.
3. Talk to professional staff in your favorite bar or bottle shop, learn what they have to share from their experiences.
How about doing 3 things at once? Join our Homebrewing Workshop! That way, you can learn more about the brewing process, try different beers, and learn more beer knowledge from our professional Beer Judges! Easy peasy, lemon squeezy!
Further readings:
- Last Call for IBUs: Fact, Fiction and Their Impact on Your Beer
- What's The Meaning Of IBU?
【突破盲腸行動組・IBU究竟係乜東東？】
去酒吧睇酒單，或者睇啤酒招紙，有時都會見到「IBU」呢三個字母。究竟IBU係乜東東？IBU數值又點樣幫到大家揀啤酒？
IBU全寫係International Bitterness Units，係一個用嚟計算啤酒「苦度」嘅方法。喺釀酒過程中，煲熱咗啤酒花之後，裡面嘅α酸(alpha acid)會異構化、並溶解喺啤酒之中；而IBU就係計算啤酒裡面α酸異構物(iso-alpha acid)嘅水平。
簡單啲嚟講，IBU數值愈高，「理論上」隻啤酒會愈苦。
點解要強調係「理論上」呢？因為IBU只係一個化學上計算苦度方法，同真實感知苦度(perceived bitterness)未必相等。
IBU vs 感知苦度
感知苦度有幾高，可以受多個因素影響——例如甜味可以影響人對苦味嘅感知度。舉個例，一杯有60 IBU嘅黑啤，對比起只有50 IBU嘅淡愛爾(Pale Ale)，飲起上嚟可能反而係50 IBU嘅淡愛爾比較苦。因為黑啤裡面嘅麥芽甜味能夠平衡苦味，所以飲起嚟味道會冇淡愛爾咁苦。就好似煮嘢食咁，落多咗糖，自然味道會冇咁苦啦！
1000 IBU？
另外，人嘅味覺對於苦度嘅感知度有限，我哋實際上只能夠分辨到12 至 80 IBU左右，所以90 IBU嘅啤酒「理論上」比80 IBU苦啲，但實際飲起上嚟可能係差不多！
市面上亦有啲啤酒標榜IBU高達1000，但因為人體實在分辨唔到咁高IBU，所以對我哋嚟講，1000 IBU同100 IBU飲落可能係一樣——都係苦過弟弟😅！
IBU算式嘅漏網之魚？
除咗感知苦度之外，IBU都未必可以計算到其他影響啤酒苦度嘅因素！啤酒嘅苦味主要來自於啤酒花，但部份深色麥芽(例如黑麥)、香料其實都可以令啤酒變苦，但係IBU未必能夠計算在內。另外，冷泡啤酒花法(Dry-Hopping) 亦都可以喺唔製造α酸異構物(iso-alpha acid)嘅情況下令啤酒味道變苦。喺呢兩個情況之下，IBU就未必反映到啤酒真實嘅苦度啦！
有啲啤酒冇寫IBU嘅？
有時啤酒招紙上面冇寫到IBU，咁又係點解嘅呢？部分啤酒因為並唔係以啤酒花為主導（例如酸啤），所以IBU對呢啲啤酒嚟講並唔係最有用嘅資訊，所以部份酒廠會選擇唔寫出嚟。IBU主要係一個參考資料，唔同酒廠會有佢哋自己嘅原因選擇透唔透露IBU呢個資訊。
IBU究竟幫唔幫到手㗎？
睇到呢度你可能會問：IBU都唔完全反應隻啤酒苦唔苦，既然係咁，IBU咪唔係好幫到手？其實都唔係嘅！IBU數值可以令飲啤者有心理準備，知道杯啤酒有幾苦。對於一啲對苦度十分敏感嘅人，IBU可以幫到手，令佢哋揀啱適合佢哋飲嘅啤酒。
而行內亦有好多專業人士研究緊點樣令到IBU計算方法更加準確，所以假以時日，IBU有可能會更加幫到我哋去分辨啤酒嘅苦度！
我哋有幾個貼士可以比有興趣了解多啲關於IBU嘅你：
1. 認識唔同嘅啤酒酒款，了解吓不同酒款常用嘅麥芽同啤酒花種類、同佢哋嘅釀造過程
2. 試多啲唔同IBU嘅啤酒，體驗吓唔同原料、釀酒方法對啤酒苦度嘅影響
3. 同專業嘅酒吧、啤酒舖職員傾吓計，了解所賣嘅啤酒嘅感知苦度
做齊呢三樣嘢，儲多啲經驗，就自然會愈嚟愈識揀最啱自己嘅啤酒啦！
咦咪住，有咩辦法可以一次過做齊三樣嘢？報名參加我哋嘅自釀啤酒工作坊啦！又有得學釀酒，又有得試酒，又有專人講解啤酒知識，一次過滿足三個願望！
延伸閱讀：
- Last Call for IBUs: Fact, Fiction and Their Impact on Your Beer
- What's The Meaning Of IBU?
#PowerToTheBeerDrinker #HereForBeer #HKBrewcraft
