A practical procurement guide for biochar carbon project developers working under Puro.earth, Verra BCM001 or the European Biochar Certificate. What sampling and monitoring equipment your team actually needs, what the auditor expects to see documented, and what you can skip. Written for project developers, not general equipment buyers.
This is a field equipment guide for biochar carbon project developers working under Puro.earth, Verra's BCM001 methodology, or the European Biochar Certificate (EBC). It covers the sampling, monitoring and documentation equipment your team needs on site — what to buy, what the auditor expects to see, and what you can skip.
Biochar project field work is less physically demanding than forestry surveys but requires rigorous chain-of-custody documentation. Most of the equipment cost is low — the challenge is protocol, not kit.
Puro.earth, Verra BCM and EBC share a core set of monitoring requirements that determine what field equipment you actually need versus what you might think you need.
Documented feedstock source and quantity (weight tickets, delivery records), production records (time, temperature, batch volume), biochar sample chain of custody from production through to accredited laboratory testing, H/Corg ratio and stable carbon content from an approved lab, and application site records for soil application projects. Equipment that cannot produce datestamped, signed records is significantly less useful than equipment that can.
Biochar samples must be representative of each production batch. Puro requires composite sampling — multiple subsamples taken from different points in a batch and combined before dispatch to the lab. The specific number of subsamples and the sampling protocol vary by methodology version, so check your approved methodology before finalising your sampling procedure.
Samples must be sealed immediately after collection to prevent contamination or moisture change, labelled with batch identifier, date and operator signature, and stored in conditions that prevent degradation before they reach the lab. Cool, dry, sealed storage is the minimum. Refrigerated transport is required if the sample will not reach the lab within 48 hours in warm climates.
Samples labelled only with a batch number and no date or operator signature. Samples stored unsealed or in conditions where contamination is possible. Labs not on the methodology's approved laboratory list. A single composite sample per production run when the methodology requires separate samples for different temperature ranges or feedstock batches. Gaps in the production log — days or shifts with no records.
Most small biochar producers are surprised by how low the equipment cost is relative to the verification cost. The bottleneck is documentation protocol, not instrumentation.
| Setup | Scale | Key equipment |
|---|---|---|
| Micro-producer (<50t/year) | Single kiln or TLUD unit, farm-scale | Whirl-Pak sample bags, permanent marker, budget phone for KoboCollect, cool bag for sample transport |
| Small producer (50–500t/year) | Multiple kilns or continuous pyrolysis | All above plus label printer, soil pH meter, data logger for kiln temperature, cool box for lab dispatch |
| Large producer (>500t/year) | Industrial continuous or batch process | Full sampling kit, multiple loggers, Chromebook for data management, dedicated sample refrigerator, potential LIMS integration |
Whirl-Pak sterile sample bags are the standard for biochar sample collection — they seal without contamination risk, are labelled reliably, and are accepted by accredited labs worldwide. Do not use zip-lock food bags or unsealed containers. The bags must be sealed before the sample cools significantly if moisture-sensitive analysis is required.
For soil application sites where you are taking soil core samples to document baseline carbon content and post-application change, a T-handle soil core sampler is the right tool. Stainless steel, non-contaminating, reusable. For composite sampling, collect cores from multiple points across the application area and combine into a single Whirl-Pak before sealing.
A cool box (Coleman Xtreme or equivalent) handles transport from site to lab for samples that need refrigerated dispatch. For samples going by courier, use a sealed insulated box with frozen ice packs — the lab should advise on their specific requirements.
Every sample bag must be labelled immediately at the point of collection. Handwritten labels on Whirl-Pak bags with a permanent marker are acceptable for most methodologies, but a portable label printer (Brother P-touch H110) produces more legible, durable labels and reduces transcription errors when batch codes need to match production records exactly. For producers running multiple kilns with high batch volumes, the time saving and error reduction justifies the cost.
Biochar production temperature determines the degree of carbonisation and therefore the H/Corg ratio that your credit yield depends on. Puro requires documented production temperatures for each batch. For continuous pyrolysis units, the kiln's onboard instrumentation typically handles this. For batch kilns (traditional flame-curtain, Adam retort, TLUD), you need a standalone data logger or thermocouple system.
The Govee CO2 and temperature monitor covers ambient monitoring at the production site. For in-kiln temperature logging, you need a high-temperature thermocouple (600–1200°C range) rather than a standard data logger — this is specialist instrumentation that goes beyond what's covered in this guide. If your kiln manufacturer does not provide integrated temperature logging, contact your methodology's technical team before investing in instrumentation.
Production records, sampling logs and delivery documentation should be captured digitally where possible, with signed paper backup. KoboCollect is appropriate for structured data entry — batch records, sampling events, delivery confirmations — and produces exportable datasets that simplify annual reporting. A budget Android phone runs KoboCollect reliably and costs less than the lab analysis fee for a single biochar sample.
For the office or site hut where data is consolidated, reviewed and submitted to the registry, a Chromebook handles KoboToolbox web interface, Google Sheets for production tracking, and PDF export for audit packages. The auto-update and malware resistance of Chrome OS reduces IT risk at remote production sites where IT support is unavailable.
For projects claiming soil application co-benefits (improved soil pH, water retention, crop yield), baseline soil measurements are required before application and at defined monitoring intervals post-application. A calibrated digital pH meter (Apera PH60 or Bluelab pH Pen) provides the accuracy needed for baseline documentation. A 4-in-1 soil meter (pH, moisture, temperature, light) is sufficient for preliminary screening but not for baseline records that go into a monitoring report — use a dedicated calibrated pH meter for those readings.
Not equipment failure — documentation gaps. A batch with no timestamp in the production log. A sample bag with only a batch number, no date or operator name. A lab report that does not match the batch identifier on the sample bag because the code was transcribed differently. A gap of several weeks in the production records because 'nothing was happening' — but Puro requires continuous records of all production periods including idle periods. Invest in the protocol before investing in equipment.
The equipment list for a small biochar producer is short and inexpensive. The documentation protocol is what takes time to establish and what auditors scrutinise most carefully. If you are approaching your first verification, ask your verifier (VVB) to review your documentation system before your monitoring period begins rather than after.