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WonderScience fact

Honey keeps for a remarkably long time. It is only about 18% water, with so much sugar that it draws water out of microbes instead of feeding them, and it is acidic enough to stop many of them growing. Kept sealed, it does not go off.

Biology

Science

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Bees work hard for this. Nectar is 70 to 80% water; bees evaporate most of it in the hive, then cap each cell of finished honey with wax. They also add an enzyme, glucose oxidase, which produces gluconic acid and small amounts of hydrogen peroxide, a mild disinfectant. Honey's average pH is about 3.9. Its weak point is moisture: honey draws water from damp air, and if it takes up too much, the yeasts in it start to ferment it, which is how mead is made. Honey is not sterile, though. It can carry dormant spores of the bacterium that causes botulism, harmless to adults but risky for babies, so it should not be given to children under one. The oldest known honey remains, found in clay jars in an ancient tomb in Georgia during the building of an oil pipeline, are between 4,700 and 5,500 years old.

Türkçe oku
Bal olağanüstü uzun süre dayanır. Yalnızca %18 kadarı sudur; içindeki şeker o kadar yoğundur ki mikropları beslemek yerine onların suyunu çeker. Asitliği de birçok mikrobun üremesini engeller. Ağzı kapalı tutulduğunda bozulmaz.

Bu dayanıklılık arıların emeğidir. Çiçeklerden toplanan nektarın %70-80'i sudur; arılar kovanda bu suyun büyük kısmını buharlaştırır, olgunlaşan balın bulunduğu gözeleri de balmumuyla kapatır. Bala glukoz oksidaz adlı bir enzim de katarlar. Bu enzim glukonik asit ve az miktarda hidrojen peroksit üretir; hidrojen peroksit hafif bir mikrop öldürücüdür. Balın ortalama pH değeri 3,9 civarındadır. Balın zayıf noktası nemdir: Nemli havadan su çeker ve fazla su alırsa içindeki mayalar çalışmaya başlar, bal mayalanır; bal şarabı da bu yolla yapılır. Yine de bal steril değildir. Botulizme yol açan bakterinin uykudaki sporlarını taşıyabilir. Bu sporlar yetişkinler için zararsızdır, ama bebekler için tehlikelidir; bu yüzden bir yaşından küçük bebeklere bal verilmemelidir. Bilinen en eski bal kalıntıları, Gürcistan'da bir petrol boru hattı inşa edilirken eski bir mezardaki toprak kaplarda bulundu ve 4.700 ile 5.500 yıl öncesine tarihlendi.

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