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Lemon Juice, to Purify
Strain one pint of lemon-juice through muslin; mix with it half an ounce of pounded charcoal, and let it remain until the next day; run it through blotting-paper, so as not to disturb the sediment. Bottle it, cork it tightly, and tie bladder over the corks. Keep it in a cool, dry place. Probable cost of lemons, 1d. each.
This is a keeping method rather than a dish: charcoal is used to strip colour and off-flavours from pressed lemon juice so it can be bottled and held. The hinge is that the charcoal clarifies but does not sterilise, so storage matters more than the filtering.
- The pint is imperialCassell's pint is 20 fl oz, so about 570 ml of juice, which takes roughly 12-16 lemons depending on size. Half an ounce of charcoal is about 14 g.
- Use food-grade charcoalVictorian "pounded charcoal" was charcoal crushed in a mortar, usually wood but sometimes animal (bone) charcoal, which was also used for decolourising. Modern barbecue charcoal is often treated with binders and accelerants; only food-grade activated charcoal is appropriate, and being more adsorptive it works faster than plain crushed charcoal.
- Blotting paperUnsized blotting paper was the standard fine filter of the period. A paper coffee filter or a double layer of cheesecloth over a fine sieve does the same job; pour gently so the black sediment stays in the jug.
- Bladder over the corkA softened pig's bladder tied over the neck shrank as it dried and pulled tight over the cork, giving a close seal. A sterilised bottle with a screw cap or a swing top serves the same purpose.
- This is not a preserving processNothing here is heated, so wild yeasts and moulds survive. Lemon juice is acidic enough that spoilage shows as surface mould or fermentation rather than anything dangerous, but the bottle belongs in the refrigerator and is best used within a few weeks. Freezing in ice-cube trays keeps it far longer.
- What the charcoal does and does not doActivated charcoal adsorbs colour, bitterness and some aroma compounds. It will not remove the acidity, and it strips out a good deal of the fresh lemon character along with the murk.
- Cost noteThe "probable cost" of a penny a lemon is the kind of costing Cassell's routinely supplied.
- YieldExpect a little under a pint after filtering; the charcoal and sediment take their share.
Preserving lemon juice was a serious domestic concern before reliable year-round citrus imports and refrigeration. Fresh lemons reached Britain seasonally from the Mediterranean, and a household that wanted acid for punch, jellies, sauces and medicine out of season had reason to bottle it. Charcoal was the Victorian purifier of choice for almost everything: it was packed into water filters, used as a deodoriser, and used in refineries to decolourise sugar, so applying it to cloudy lemon juice followed the logic of the age. The instruction to tie bladder over the corks is a reminder of how sealing was done before reliable screw caps, and the note on cost, a penny a lemon, is typical of Cassell's, which priced most entries so a housekeeper could reckon whether the labour was worth it.