How many kilograms of fresh lotus root make 1 kg freeze-dried, and why does the colour stay ivory?
About 7–8 kg of whole lotus root as harvested, or 6.0–6.5 kg once it is washed, peeled and trimmed, makes 1 kg of freeze-dried lotus root. The colour stays ivory because the root is cut and blanched within minutes of peeling, before its own enzymes can brown it. No sulfites are used, and no acid dip unless your formula asks for one.
Those two facts are the quickest way to read a quote. A price that only works on 4–5 kg of fresh root per kilo is either buying water you will pay for at the dry-product price, or getting its yield somewhere you will not like. A slice that is whiter than lotus root naturally is has usually been helped. This guide shows where the weight goes between the pond and the bag, how the colour is kept, and how to test any quote, including ours, before you sign.
Where do 7–8 kg of lotus root go before they become 1 kg?
Mostly into the air as water, and the rest into the trimming bin. Lotus root is 79–83% water and grows in pond mud, so it loses weight twice: once at the washing and peeling line, and again in the freeze dryer.
| Basis | Fresh root per 1 kg freeze-dried | What is counted |
|---|---|---|
| Whole roots as harvested | ≈7–8 kg | Roots as bought from the farm, with mud, skin, joints and tips |
| Washed, peeled and trimmed | 6.0–6.5 kg (5.5–7.0 by season and cut) | Clean flesh that goes to the slicer |
| Theoretical floor | 4.6–5.7 kg | Flesh at 79–83% water dried to 4% moisture with zero process loss |
The first kilo or so goes before the root is ever sliced. Mud is packed inside the air channels and has to be pressure-washed out, the skin comes off, and the hard joints between sections and the thin tips are cut away. Short sections and offcuts do not make round slices, so they go to dice and granules rather than to the bin, which is why the grade you buy changes your cost (more on that below).
The second gap, between the theoretical 4.6–5.7 kg and the real 6.0–6.5 kg, is the honest cost of processing. Some soluble solids leave in the blanch water, slice ends and crumbs are screened out of the grade, and no line runs at zero loss. A supplier who quotes on the theoretical floor is quoting a line that does not exist.
What 6.0–6.5 kg means for your freight. A 20ft container of whole slices carries 2.75–3.85 t, the equivalent of roughly 19–31 t of lotus root as harvested, in a standard dry container with no reefer and no thaw drip. That is the trade you are paying for when one kilo of the dried product costs more than one kilo of fresh root.
Why can a quote below 5 kg of fresh root per kilo not be right?
Because the water sets a floor. At 81% water, 4.5 kg of peeled lotus root holds about 0.86 kg of dry matter. Dried to 4% moisture with no loss at all, that makes 0.89 kg of finished product, not 1 kg. The missing 11% has to come from somewhere.
In practice it comes from one of three places, and each one costs you more than the discount:
- Moisture left in. A lot shipped at 8% moisture instead of 4% carries about 40 kg more water in every tonne, paid for at the dried price. The slices bend instead of snap, and water activity climbs toward the level where a porous slice goes leathery in your customer’s pantry.
- Joints and tips cut into the slice grade. The weight stays in, the round 7–9-hole wheel does not. You see misshapen, woody pieces in a pack sold on its pattern.
- A different basis. The quote counts peeled flesh while you assumed whole roots, or the reverse. Neither is dishonest on its own; mixing them up in a comparison is.
Ask every supplier which basis their ratio is on, whole or peeled, and ask for moisture and water activity on the COA of the lot you are buying. The release limits FruitBuys works to, moisture 3–5% and Aw below 0.30, are set out in what a freeze-dried lotus root COA should prove.
How is lotus root processed from the pond to the bag?
Fast at the start, slow at the end. The first steps race the browning enzymes; the freeze dryer then takes its time so the slice keeps its shape.
- Wash. Roots are pressure-washed and the air channels inspected for mud before anything else happens. Soil in the channels is the lotus root defect that reaches the consumer, so this step is where it is stopped.
- Peel and trim. The skin, the hard joints and the tips are removed. Peeled sections go straight into cold water so the cut surface is not left in the air.
- Slice or dice. Internode sections are cut into whole slices of Ø 40–60 mm × 3–5 mm, with the 7–9-hole wheel intact. Smaller sections are cut into dice of 5 × 5 mm, 10 × 10 mm, 3/8″ or 1/4″, or into granules.
- Blanch. The slices are blanched to inactivate the browning enzymes, then cooled.
- Freeze and freeze-dry. The slices are frozen and dried under vacuum, where the ice turns straight to vapour, to 3–5% moisture and water activity below 0.30. Because the water leaves as ice, the porous structure and the wheel pattern hold their shape.
- Grade, check and pack. Whole wheels, half slices and pieces are graded, passed through metal detection, and packed in foil bags with food-grade silica gel desiccant.
The whole run takes place at one qualified partner facility locked to your contract. Any change of facility needs prior written notice and re-approval of your pre-shipment sample, and you have audit access.
Why does lotus root turn brown, and how is the colour kept ivory?
Lotus root is rich in polyphenols, and it carries the enzyme that turns them brown (polyphenol oxidase) the moment the cut surface meets air. A peeled root left on a table for a few minutes starts going pink-grey, then brown. Once that colour forms, no amount of drying takes it out.
The line beats it with time and heat rather than chemistry. Peeled sections go into cold water within minutes, are sliced, and are blanched, which switches the enzyme off for good. After that the slice is frozen and dried under vacuum, so nothing in the process has the chance to darken it. The result is a natural ivory to light cream, the colour of freshly cut lotus root.
Two things follow for your shelf. Your ingredient line can read simply “lotus root”. And when your retail QA asks whether the slice was bleached, the answer is no, and you can prove it.
What to check, with any supplier including us. Hold the sample against a freshly cut root. A natural ivory with a faint cream tone is what good handling looks like. A grey or brown cast means the root waited too long before the blanch. A chalk-white slice, brighter than fresh lotus root ever is, is worth a sulfite test before you approve it.
Does dried lotus root contain sulfites?
Not from FruitBuys: no sulfites are added at any step, and a sulfite result below 10 mg/kg is available as an optional panel for your lot. That number matters because 10 mg/kg is the labelling threshold for sulfites in the US and the EU: above it, sulfites must be declared.
Sulfites are a known shortcut in dried Asian plant foods. They keep a pale colour cheaply, and they are behind repeated US recalls of products such as dried lily flower and dried bamboo shoots that reached shelves with sulfites not declared. For a buyer, an undeclared sulfite is a recall and a delisting, not a quality footnote. If you sell into the US, or print “no sulfites” on pack, add the sulfite panel to the contract so the result travels with the lot.
When does a citric acid dip make sense, and what does it do to your label?
Only when your formula asks for it. By default the slice is processed with no acid dip, and the label stays at one ingredient.
A light citric acid dip before the blanch gives a slightly brighter, whiter slice, which some buyers want for a clear broth or to match an existing product. A light salt blanch is the other option, for a savoury snack built to your own recipe. Both are run on request for OEM programmes, and both change your label: the ingredient line becomes “lotus root, citric acid” or “lotus root, salt”, and the single-ingredient claim no longer applies to that lot. Decide on the label first, then the pretreatment.
Does the ratio change through the year?
Yes, within a known band of 5.5–7.0 kg of peeled root per kilo. Lotus root is lifted 5–6 months after planting, and staggered planting across Dong Thap keeps fresh roots coming through the year, but not every root is the same. Mature roots carry more dry matter and convert at the low end; younger, wetter roots sit at the high end. After heavy rain, roots come out of the pond with more mud, so the whole-root figure moves even when the peeled figure does not.
Slice thickness moves it too. The thinner the slice, the more surface loses solids in the blanch and the more slices break in handling. An ultra-thin 2 mm chip looks elegant in a photo, but it raises the fresh root needed per kilo and arrives with more broken pieces. FruitBuys recommends 3 mm as the thinnest whole slice that travels well. If what you need is lotus root in a tea blend or a soup base where the slice is broken anyway, half slices, dice or granules use the short sections and offcuts, and give you a lower cost per usable kilo. The formats are compared in which freeze-dried lotus root format fits your line, and the growing season in where Vietnam’s lotus root grows.
How do you test a lotus root quote before you sign?
Compare quotes on what lands in your warehouse and what your line can use, not on the invoice figure. Fill in this line for each supplier:
Cost per usable kg = (price per kg + freight per kg + import duty at the declared code + any additional US tariff in force on the entry date + broker and port fees per kg) ÷ share of the lot that meets your grade
Two inputs decide most of the answer.
- Grade share. If 15% of a whole-slice lot arrives as broken pieces your line cannot use, every usable kilo costs 1 ÷ 0.85 = 1.18 times the landed figure. Write the broken-piece allowance into the contract and check it on arrival.
- Freight per kilo. Whole slices pack 5–7 kg per carton, dice 7–9 kg, in the same 58 × 28 × 34 cm carton. With about 550 cartons in a 20ft, freight per kilo on whole slices runs roughly a third higher than on dice. If the wheel pattern is not on show in your product, dice are the cheaper way to ship the same root.
Then ask each supplier the same five questions in writing:
- Is your ratio on whole roots or on peeled root?
- What moisture and water activity will the lot COA show?
- Which pretreatments are used: sulfites, citric acid, salt, none?
- What share of whole wheels and broken pieces is in the slice grade?
- Will you send a pre-shipment sample from the packed lot, and hold the container to it?
A supplier who answers all five in writing is giving you a quote you can compare. FruitBuys answers them in the specification on the freeze-dried lotus root product page.
Send your RFQ with the grade and label you need
Tell us the format, the slice thickness, your label line (one ingredient, or with citric acid or salt) and the destination market, and the quote comes back on a stated basis: whole or peeled ratio, moisture and Aw on the COA, grade split and the panels your market needs, with a pre-shipment sample from the packed lot.
FAQ
How much fresh lotus root makes 1 kg of dried lotus root?
About 7–8 kg of whole roots as harvested, or 6.0–6.5 kg once washed, peeled and trimmed. Over the year the peeled figure moves between 5.5 and 7.0 kg with root maturity and slice thickness.
Why does lotus root turn brown after peeling?
Its own enzyme, polyphenol oxidase, browns the polyphenols in the cut surface as soon as it meets air. Cold water straight after peeling and a blanch before freezing stop it.
Does freeze-dried lotus root contain sulfites?
FruitBuys adds no sulfites at any step. A sulfite result below 10 mg/kg, the US and EU labelling threshold, is available as an optional panel on your lot.
Is citric acid added to keep lotus root white?
Not by default. A citric acid dip is available on request for OEM formulas, and then “citric acid” appears on the label.
Why does freeze-dried lotus root cost more per kg than fresh?
Each kilo carries 7–8 kg of harvested root and a long freeze-drying cycle. In return a 20ft container of slices carries the equivalent of roughly 19–31 t of fresh root, in a dry container with no cold chain.
What colour should freeze-dried lotus root be?
Natural ivory to light cream, like freshly cut root. A grey or brown cast points to slow handling; a chalk-white slice is worth a sulfite test.
What slice thickness should I order?
3 mm is the thinnest whole slice that travels well. Thinner slices need more fresh root per kilo and break more; 3–5 mm is the standard range.
