Microbial contamination in barrels, particularly the presence of Brettanomyces, remains one of the main challenges in the production of aged wines. Controlling these risks without compromising the enological potential of the barrel is now a priority for many wineries.
In this context, BARENA emerges as a process that goes beyond simple barrel cleaning, offering a way to regenerate the barrel from within, restoring its enological functions while simultaneously reducing microbiological risk.
In this interview, we speak with Alvin Miranda, Commercial Director of BARENA, about the technical foundations of this barrel regeneration system and its practical application in the winery. An agronomist and oenologist trained at the University of Chile and the Polytechnic University of Madrid, Miranda specialises in oenological microbiology and is the author of several studies on Brettanomyces and microbiological contamination in wines.
Based in Viana (10 km from Logroño), BARENA has already regenerated more than 200,000 barrels for over 400 wineries. In a context where wineries aim to balance enological quality, microbiological control, and economic sustainability, barrel regeneration is becoming an increasingly valuable technical solution.
You are an agronomist and oenologist, with a background in oenological microbiology… What convinced you, from a technical standpoint, to join BARENA?
My training in oenological microbiology and my experience in barrel management showed me that working with barrels that have been used more than once is a critical point, both from a sanitary and a sensory perspective. The BARENA regeneration system convinced me because it simultaneously addresses deep decontamination, the physico-chemical restoration of the wood, and the functional recovery of micro-oxygenation, with a solid technical base and analytical validation. It is not simply cleaning: it is oenological re-engineering of the barrel.
The challenge of reusing barrels is not new in itself. But the BARENA process is the only “integral” one. Can you explain what sets this technology apart from others, from an oenological perspective?
Most systems act on the inner surface and alter it; BARENA works integrally on the ligneous matrix, eliminating contaminants in depth and restoring the toasting profile and the capillary structure of the oak. From an oenological standpoint, this means recovering controlled release of phenolic compounds and gas exchange capacity, restoring the barrel’s micro-oxygenation and, ultimately, returning its function as an active vessel. The barrel’s active lifespan is extended with full oenological efficacy — not simply as an inert container.
The elimination of brettanomyces is one of BARENA’s central arguments. Why do conventional cleaning methods — steam, chemical products — not fully protect against this threat?
Brettanomyces bruxellensis can lodge in the deep layers of the wood, where steam, disinfectants or other methods do not reach sufficient concentrations or contact time. Used barrels have their surface partially blocked by crystallised solids — tartrates and phenolic precipitates — which prevents the effective penetration of sanitising agents and makes deep decontamination of the wood impossible. Microbiological contamination in a barrel cannot be resolved at surface level.
The BARENA system first eliminates these solids and reopens the capillary structure, enabling deep cleaning and aseptisation. The elimination of brettanomyces in wine — and in wood — requires this prior opening of the pores: without it, no matter how much steam is applied, the yeast remains protected. BARENA does both: it opens the pore, then saturates it with steam. The result is a real and verifiable reduction in the risk of recontamination.
The opening of the pores and the restoration of micro-oxygenation are two key concepts. Can you explain, with concrete data, how they impact the organoleptic profile of the wine?
The restoration of porosity improves the oxygen transfer rate (OTR), bringing it to ranges comparable to younger barrels: approximately 10–45 mg O₂/L/year depending on origin and toasting level. This promotes tannin polymerisation and colour stabilisation, reducing green astringency and enhancing aromatic volume and complexity.
The release of ellagic tannins and volatile compounds derived from toasted oak recovers measurable levels in comparative studies. On the sensory level, this translates into better wood-fruit integration and a silkier texture on the palate — exactly what the current market for aged wines demands.
From what age should you regenerate? Protocol and barrel fleet management
Infowine: From what age or condition of the barrel does it make sense to consider BARENA regeneration, and when is it no longer recommended? Is there a prior diagnostic protocol?
Scientific studies conducted since 2008 indicate that it makes sense to treat barrels from 3–5 years onwards, when release diminishes and microbiological risk increases. However, more recent trials show that barrels treated even after the first wine can display aromatic wood compound releases higher than those of a new barrel. It is therefore important to understand what this technology is capable of contributing and how it fits into the ageing profiles of each winery.
The limit is always personalised: barrels with structural fatigue or deep chronic contamination are not optimal candidates. When discussing the regeneration of a barrel, the decision depends on the real condition of each individual unit. The protocol must include physical inspection, microbiological analysis where necessary (Brett by PCR) and sensory evaluation.
How can barrel regeneration be integrated into fleet management at a high-volume winery without disrupting ageing cycles?
Regeneration must be planned as an annual rotation of the fleet, aligned with racking and post-ageing emptying. With precisely planned logistics, it can be integrated without affecting production cycles, functioning as a strategic asset management tool. In technical terms, it is predictive maintenance of the ageing system. The barrel’s active lifespan is thus managed as a strategic asset, not as a fixed cost.
Your clients even carry out malolactic fermentation in regenerated barrels. What technical conditions make this use possible, one normally reserved for new barrels?
Deep decontamination and the recovery of oxygen kinetics create a stable environment for lactic bacteria. With controlled microbial loads and adequate prior hydration, the regenerated barrel can behave analogously to a young barrel. This allows winemakers to carry out malolactic fermentation in regenerated barrels with greater microbiological safety and structural contribution.
Some of our clients now carry out malolactic fermentation even in regenerated barrels of more than five years, with sensory results equivalent to those obtained in new barrels. It is one of the uses that has most surprised even the most sceptical oenologists.
BARENA claims that a regenerated barrel of 5–7 years recovers the characteristics of a 2–4 year barrel. What analytical parameters — ellagic tannin release, oxygen exchange, sensory analysis — support that claim?
The scientific studies evaluate ellagic tannin release and volatile compounds derived from toasted oak, OTR measurement in oak barrels, and post-treatment microbiological analysis. These comparative trials show a significant recovery of gas exchange and a reduction of Brett to levels undetectable by PCR. Validation is completed with descriptive sensory analysis and triangular tests. The complete study results are available on BARENA’s website.
The wine sector is going through a margin crisis. How do you, as an oenologist, frame the decision to regenerate barrels: is it primarily an economic lever, or above all a quality decision?
It is both, but it must start from quality. In a context of margin pressure, optimising barrel fleet management without compromising the sensory profile is an intelligent technical decision. Profitability is the consequence of sound oenological management.
In what direction is BARENA’s technology evolving? Are there ongoing developments that would allow the organoleptic result to be further refined according to the target wine profile?
The evolution involves greater precision in modulating sensory impact, adjusting the moment of application and deepening parameters according to oak origin, toasting level and wine style. The objective is for regeneration not only to recover functionality, but to allow the organoleptic profile to be refined in a predictable and measurable way. Barrel regeneration is moving beyond a maintenance decision to become a precision ageing tool.
For more information or technical advice:
alvin.miranda@barena.es
https://barena.es/en/home-english/
